Back when I was in college, I bought a Dreamcast and a copy of Marvel Vs. Capcom 2, and played a metric ton with my roommates. We actually maxed out the "time played" counter at 99 hours that summer. The thing about MvC2 is that it looks like a button-masher, but if you're at all competitive (and we were), it becomes a gateway to systematic obsession with the underlying mechanics of Capcom fighters. The Dreamcast was also the first chance I'd really had to experience the SNK style of fighting game, via Garou: Mark of the Wolves. You couldn't pick two more extreme examples, really: one being a hyperkinetic display of increasingly ridiculous special moves, while the other featured a slower, tactical focus on basic technique executed well.
Super Street Fighter IV falls as much on the SNK side as Capcom is likely to get, post-Third Strike. It's slower and more deliberative than previous iterations, with a greater emphasis on basic moves, and the dual special meters (Capcom loves special meters like Square loves RPG menus) serve to keep matches unpredictable by linking one to offense and the second (more powerful) meter to damage taken. Several of the new characters (Juri and C. Viper in particular) have a very SNK-like flavor, both in their character designs and the feel of their special moves. They also borrowed the "ridiculously cheap final boss" design, although he's toned down markedly from the non-Super version of the game.
Maybe they didn't borrow enough, though. SSIV is apparently meant to be a reboot of the series for the kind of people who, unlike me, are not interested in the nuts and bolts--the kind of people who have no idea that there are 2D fighters that aren't Street Fighter. But that isn't actually backed up by its execution. Part of what I liked about the SNK fighters is that they were diverse in character style, and special moves were almost consciously depowered. SSIV, on the other hand, continues Capcom's love affair with the Ryu/Ken shotokan move set: fully a quarter of the characters are variations on this basic template (seven, if you include Sagat). There are a lot of multi-button special triggers, some of which are overloaded (a two-button chord fires a different move than three buttons), which makes it easy to whiff on the intended move. Plus, I've got a pretty good history with the series, and I still can't pull off half of the super combos consistently, particularly the charge-based ones. I can't imagine a real newcomer jumping in without a lot of frustration.
If I were designing a casual fighter for the home console crowd (and, let's be honest: given the decline of arcade gaming, that's what they're doing here), it seems to me like the first priority would be to drop the classic six-button layout and switch to the MvC2 four-button scheme. There hasn't been a common controller on the market with six face buttons since the Genesis, and using long-throw triggers for basic attacks in Street Fighter is a timing disaster. SFIV uses all six buttons, combining them with some directional movement for alternate attacks, which is a lot for ordinary people to grasp. Although I don't typically enjoy 3D fighters, this is one thing that they got right.
And then I would think very carefully about what a "casual" 2D fighter actually means. It would be great for such a game to introduce new players to the actual, hidden dynamics of a "fighting" game: control of space, timing, priority, and reading your opponent. Piling on with a second (segmented) super meter, two-button counters and specials, and motions like "↓↘→↓↘→PPP" overcomplicates matters. It seems like they're trying to have their cake and eat it too--taking out "advanced" (but easy-to-understand) mechanics like parries and air-blocking, but refusing to cut back on years of tournament-player feature-creep (EX cancels and specials, for example). The result seems "casual" to critics and long-time players, but it's really no more accessible than it's ever been.
Some other random thoughts:
Usually those strengths get countered with weaknesses, like a lack of long-range attacks or a difficult joystick motion. But a shoto character is all strengths: they've got a projectile (fireball), a high-priority close-in attack with anti-air and reversal (dragon punch), and a screen-covering travel attack (hurricane kick). That combination makes it easy to set traps and take control of a match. For more than a decade, a large part of the Street Fighter metagame has been devoted to overcoming the generic shotokan character, and it bores me senseless.