Thanks for the well written response. They can be tough to get around here. For someone like myself who spends about 20 minutes in practice mode with each character and gets out there and has fun, all these intricacies are lost on me. So I'm guessing these massive character lists appeal to a) the elite/hardcore competition fighters that understand how to use 30-40 different characters and all their subtleties effectively and b) the people who are "omigod 35 characters dats so kewl!". I'm obviously neither of these. I don't think anyone can argue that Ken/ryu/akuma/dan/Sakura/whoever else I'm forgetting has the same degree of difference as, say, dhalsim/zangeif/chun li. And I can swear that 1/2 of my online matches in SFIV were against Ken. Literally. So I don't really see people utilizing these massive character lists. Perhaps they do on the pro level?
/thread derailment
It's not a real derailment honestly, because you are bringing up a valid point based off your own experiences.
The situation with Ken is, he's brain dead easy to play at a 100% ass level in the sense that you can just mash shoryuken and have some success on people who are trying to learn the game and do combos, but don't have timings down, so they get interrupted by him mashing it or doing anything when he is going to stand up.
With SF4 once you grind yourself to being good enough to get out of that skill bracket you start to see a big opening in what characters are used, how good people are with them, and play styles. It's like day and night on what you are playing once you reach that point.
At pro level you'll see a variety of characters, but you'll also see consistency of handfuls (5-10) usually placing in the top spots in tournaments. That's partly due to those characters having really great tools, but of course also has to do with the person using them as well. Like Rufus is great example of a nightmare to fight at top level, but he's a joke in a novices hands as a threat.
Developers have gotten a lot better at balancing games out too, so you don't see situations like Vanilla SF4 where it was pretty much Sagat running the show, but there will always be a 1 strongest character. It's why in original BB release with it's small roster the pro level was NOTHING but V-13. It made the game awful to watch due to 1 character being so much better than the rest of the cast. Thank goodness for patches these days to nerf stupid shit like Phoenix and Yun.
So while a smaller more diversified cast to the casual may seem "better" ins ome ways, it can open up a whole different can of worms that you'll only see 1-3 characters only at pro level. Which is why I'm far more adamant of a bigger roster because it gives a chance to see more when you watch streams.
I mean take this weekend for example with Final Round stream. The guy who won UMvC3 was using characters you don't see at the top ever. Vjoe, Frank, and ROCKET Racoon of all people.
Bigger doesn't mean better, and neither does smaller, it's upt to the developer to hit that sweet spot and make each feel their own. Luckily Capcom does a great job of that imo.