Haha, okay sure, i'll bite.

In my general opinion, excluding all casual players and whatnot, focusing on those who are good enough to play expert.

Good player - most mid tier players that can maybe 99 some 9s and 10s, but isn't going to be 99'ing too many 11+s, or passing 13+s.  Most old school ddr players that didn't devote themselves to ITG/Pump tend to fall into this line

Tech Player - One that is a serious tourney threat to most people on most things 12 or under.  When I hear tech player I think BBQ *Quadded all 9s/most 10s, still half kills himself on pande or summer* and Little Matt before he bought a machine and went brute.

Stamina player - One that can maul through 13+ songs while probably looking like he just fell into a pool while doing so.  Their primary strategy in a tourney will be to wear you out before they wear themselves out....because they probably can.

Expert/Tourney/Brute player - The type where you need some kind of really good working strategy to beat.  Pick a 9 you're good at?  They've probably quadded it.  Outstamina him?  He's passed things you can't do on stepmania.  The type of player that's spent a good amount of time on the game and you can pretty much put money on placing in any tourney environment.  They're just well rounded.

Honestly, now that you put it like that, I don't think our conceptualizations of the different player types are *too* different.  The main thing I'd disagree on is where the upper bounds are.  I'd say it's more like:

Good player: What you said, but isn't going to be 99'ing any 11s or passing most 12+s.

Tech player: Serious tourney threat to most people on 9s and 10s, timing starts to decline around 11s, not a tourney threat at all on 12s+.

Stamina player: Any player for whom constant stream isn't a problem, and whose primary objective in playing the game is to exert themselves as much as possible for as long as possible.  This could mean playing all of the 11s and 12s in a row, beasting Dragonforce 26/7, etc.

Expert: Yeah, good at everything.  Obviously.

All I can say is that the statement of being "good" but not having both timing and stamina is paradoxical in that truly good players have both and in spades, so where does that leave a "good" stamina or timing player? "Good" players are casual players (or just bad) by today's standards. Same goes for "good" DDR players: you are "skilled" at what is now an irrelevant game that is an easier and all in all worse game which doesn't have the same theoretical skill ceiling as ITG.

Boundaries aside (since they're constantly sliding around with the sheer amount of content available via hacking + r21), I think the key point is the four categories.

Stamina, Tech, and "Good" (I prefer "Balanced" or "Well-Rounded" to avoid the connotations of "Good") players represent the 3 main paths for players training themselves to one day fall in the Expert category.

Since Expert players are being defined (rightfully so) as All-Rounders, the Stamina/Tech dichotomy represents an approach of mastering one thing then the other from different angles (that is, if we assume these players intend on one day becoming All-Rounder Expert players - some stamina players definitely do not seem to care about timing and some tech players really do not enjoy stamina charts and don't see reason to force themselves through something unenjoyable) whereas the Balanced approach is one of both working through identified weaknesses and training identified strengths.

I believe a lot of the tension around the tournament discussion was rooted in the ever-widening rift between Stamina and Tech players.  The split has been there for as long as I've been playing competitively, but when DDR tournaments were still the norm, it was unlikely that a player would reach the point of consistently SDGing 7/8's without being able to net respectable scores on 9's and pass most/all the 10's.  The opposite was true, too - consistency on 9's and 10's mapped to consistency on easier charts; players who studied easier charts had an edge on them, but the outcome was not a sure thing.  This also left very little slack to pick up when a specialist player wanted to round themselves out.  Worth mentioning is that DDR's lifebar was a lot less forgiving about misses than ITG or Pump - stamina players had to have reasonable timing to be able to play stamina charts in the first place.  Also worth mentioning is that easier DDR charts tended to be a lot like harder charts, but a little slower or with breaks added in - crossovers, weird rhythms, short bursts of 16th notes, and step-jump patterns can all be found in as many 6's and 7's as 9's, the 9's just use them more liberally.

Competitive ITG, on the other hand, covers a significantly wider range and skill on one end of the spectrum does not carry over to the other side so cleanly.  There are 9's and 10's which throw a lot of weird rhythms or awkward freeze patterns and you, but the crossover content is usually pretty lacking; 11's and 12's that deviate from the tried and true 16th note run and 8th note step-jumps tend to have small sections with weird timing - rather than an emphasis on weird rhythms - and the few higher ranking charts  with a lot of timing tricks seem to have disproportionately hard crossovers runs tacked on as an "apology" to stamina players (Man Crossing the Channel is a great chart, but the ending runs are noticeably harder than the earlier parts of the song even though most 11's with prolonged runs look more like the first half minus the timing tricks than the end runs).  In my opinion, the 9-11 range has a serious lack of good charts to train for 12's; there are some charts with a lot of steps, sure, but the definition of 12 seems to be "11 with fewer breaks and added crossovers" when most 11's have few (or no) crossovers, and the 9-10's with crossovers have a lack of crossovers during quick sections contrasted against tons of crossovers at low speed.  I've personally found that training for 12's can only be done by training for 12's, so Stamina players have a guaranteed win against non-Expert, non-Stamina players.

On the other hand, the general lack of tech content in 12's means the opposite is true - your ability to hammer away at 16th notes forever means nothing when someone forces you to slow down and hit purple notes, so Stamina players have a guaranteed loss.  This is worsened by the tendency of ITG charts to throw in tons of freezes (free lifebar refills), the smaller life penalty for misses (lessened need to learn to hit everything accurately to pass), and the loosened timing windows relative to DDR (when Marvelouses are added, each DDR window is tighter than the corresponding ITG window) which allow you to pass harder charts with yet more ease so long as you have the energy to do so - overall, the game was designed to let people slide through stamina charts much more easily than DDR would have allowed, and pure Stamina players have worse timing for it.

The end result of this is that Tech players feel it's no longer fair to them now that they need to make a dedicated effort to player pure stamina charts to have a chance on stamina charts and Stamina players feel it's no longer fair now that they need to make a dedicated effort to drop down to 9-10's to practice for a tournament if they want to have a chance against Tech players.  Both sides feel slighted by the ever higher time investment required to be a strong competitor and are then offended when the opposite side expresses their opposing concern, and then we have drama and a high risk of poorly conceived rules meant to act as a compromise between the two sides.

Your post rings true. About three years ago, some kid I was talking with at the arcade almost had an conniption when I tried to  explain that passing PSMO on the ITG machine wasn't as hard as passing it on DDR Extreme. I tried to explain the HUGE timing window for Greats on ITG and the obvious difference in penalties for Misses between the two games, but he insisted that "if someone can pass it on ITG, then they can pass it on DDR". I kept trying to explain the fallacy behind this with little success.

Thats not really the reason why passing songs on DDR is much harder than passing them on ITG.  Its might be a contributing factor, but its not the main reason.  The main reason is because the pads on all versions of DDR, SUCK beyond belief when compared to ITG or pump pads (even ddr pads that are "modified" to be more sensitive.  It just doesn't work that well, the pads aren't sensitive enough).  I've developed a habbit of calling it stomp stomp revolution.  

Back when I was playing about equally on a dedicab and a Boxor upgrade cabinet, most 12's were about equally hard to pass on either for me, Determinator and such included.  For a severe lightweight, the extra sensitivity of the dedicab may be a noticeable gain (I can't comment since the lightest I've been since I started playing is 170), but in general, the difference in sensitivity will not throw enough errors in there to make a significant difference when it comes to passing a chart.

To be a little more empirical:

On Extreme with default settings, 7 misses will usually cause you to fail the extra stage, 8 or 9 if they happen relatively rapidly (I think it's 10 if you just let it fail out).  On ITG, if your life bar is full, you can skip half of the final run in Determinator and still pass (I have done this multiple times in the past).  DDR's extra stage may have slightly higher life difficulty than normal (I don't actually know), but there's no way you could stop hitting notes for two measures of PSMO's runs (it's twice the BPM of Determinator, so two measures is a fair comparison) without failing immediately.  PSMO is 8th notes at 290, those runs are slower than Determinator's 24th note runs, and therefore that one measure of Determinator has more steps to be missed, yet you will still pass.