It occured in this thread that as ADV stands it currently uses movesets legal for the whole of gen 3 (including XD) but uses the game mechanics of one of the cartridges (maybe Emerald?) Firstly, does anyone know how this decision came about, and secondly, do we want things to remain that way? Thirdly, does anyone else know any further differences between different parts of the ADV collection (like in DPP, Acid Rain, Hypnosis accuracy, CB Pursuit and CB U-Turn-related bugs are all present only when using certain combinations of the cartridges for emulation for example).
Cartridge would have been easier for tournaments. VGC or JAA or w/e would've been been played on cartridges do to the logistics of purchasing enough screens and systems by local Nintendo organizers. Additionally, cartridge was far more convenient to use amongst friends due to not requiring the set up of an additional middleman. This is all hypothetical though. I'm just guessing as to how the tournaments were run as I've never attended them. I could be completely wrong about it and I doubt I'd be able to find a reliable source outside of someone else's experiences. If anyone can provide some sort of input on this, I'd love to hear it. The reason they'd stay like that today is because it goes against the precedent as M9M said. I don't know if there's really a reason to maintain this precedent in the current gen, but then again has a game with stadium-like connection features been made after gen 4 anyway? It stopped at Battle Revolution afaik. Going back and retro-tiering almost never ends well unless it's to address some game-breaking discovery. Past gens have a certain appeal in that "it's the way they've always been played". There are tons of resources out there for say GSC that would become completely invalid if we were to do something drastic like ban Snorlax or HP Electrics. Perhaps that's a little drastic compared to using slightly different mechanics, but I think my point stands to some degree. In regards to mechanical differences, I have no idea. I don't know anything about damage calculation changing off the top of my head.
In the case of Stadium it really is that big a deal. Stadium has Gen-II mechanics for Hyper Beam and Substitute, and both are pretty serious alterations (sleep being unblockable barring previous status is the basis of the cartridge lead meta, and literally dozens of matchups turn on Hyper Beam's presence or absence). To debate myself for a second, in the case of Gen-I the choice to use cartridge mechanics is to a large extent a metagame-merit-based one of "well if the official Gen-I meta is Stadium then there is no meta with old-style Hyper Beam and it was way cool", so theoretically it doesn't have to set precedent.
I believe the console games are best for mechanical purposes, not because they avoid glitches, but because they mechanically implement the clauses that we generally like to play by. Also we derived our rules from the Stadium games originally. I agree that Gen 1 Hyper Beam is cool, but ideally there could be a portable cartridge and arena game simulation both available. Both are their own metagames with their own fun aspects to them. Even Gen 2 has it's own little quirks like GSC Present really wrecking certain types of Pokemon. I would be interested in helping with research and development regarding the arena mechanics, if people were too lazy to do it by themselves. Maybe the information is out there somewhere though?
Didn't look like colosseum based on the screens if my memory serves me correctly. It could have been a precursor to colosseum or it might have been some sort of specially coded middleman to ensure fairness. Also no to desyncs; I haven't heard of any desyncs at all in GSC. Link battles always use G/S mechanics, even with Crystal v. Crystal. That's why we don't emulate Crystal when testing mechanics, since in-game battles differ from link battles.
It was in 2006 so I highly doubt it was a precursor and I kind of doubt they would put that much effort into making a specially coded middleman for "fairness". Colosseum was 2003, XD was 2005. So the whole "Present is fixed in Crystal" isn't really true. Good to know it's that straightforward.