[quote name='option.iv']I dunno about that. CvS2 offers so many ways to play with its multitude of characters and grooves. Compared to 3s, CvS2 matches look much more interesting. Maybe CvS2 is not simple enough for others to appreciate it?[/QUOTE]
CVS2 definitely has a steep learning curve. Simplicity isn't the problem. In terms of high level fighting game play, I don't think any fighting game is "simple". CVS2 has it's obvious Roll Canceling, it's emphasis on pokes/footsies, and obviously the attributes of each groove/how it affects each character.
Though 3S is still running strong, it has it's share of high level/not-so-simple tactics such as Charge Partitioning (which is rough since I'm learning Urien at the moment), Kara Canceling and so on.
We have hit sort of a brick wall with CVS2 though. Though it has a huge cast of characters and 6 grooves to choose from not every character benefits from said grooves. Sure it's fun to run an S-Bison, C-Morrigan, K-Ryu, but in terms of high level play you'll rarely see that. You'll rarely see top players pick characters that don't benefit from the groove they are in. Certain characters need Roll because Roll Canceling is a huge benefit (Vega), others need Run/Short Jump (Hibiki), some benefit from the aggressive/offensive nature of K (Rolento, Ken, Sagat, Cammy), and some benefit from breaking stock (Akuma, Morrigan). As with MVC2, it's hard to win tourneys with random characters, especially in a team based setup. CVS2 being: Meter Builder/Meter Whore/Clean-Up
As fun as it is to see people running random characters in grooves that are just as random or give said character any benefits, it's just don't happen at high level play. IMO high level play and it's state/evolution determines if a game is considered "dead" or not.
A-Groove has it's set cast, same with N, C, K and P. Also as I mentioned there just aren't enough new high level players anymore. The ones that are top either have moved their focus to other games or just don't care to play anymore (BAS).