According to Viscant, characters like Chun and Cammy are strong because, aside from their fast walkspeed, they can convert to big damage from lights (Chun can low jab, stand strong, low forward xx special, Cammy can low jab, target combo). Combine that with good buttons and they can stay on you and just pressure and frame trap.
Pretty sure BAS agrees since he was claiming in the Beta that Cammy was "easy char, easy wins".
I'd argue both are true, footsie and reads oriented - that the footsie aspect of the game is the gateway to the frame trap oriented stuff. Part of my feeling this way might come from playing exclusively Rashid, whom, imo, lacks in the footsie department, so it feels like I really have to earn my way in versus a character like Chun because her footsies are a wall.
The difference is that you can't really rely on pure space control just like in games like Alpha 2 and CvS2 pre-roll cancels. In the former, you can have someone like Rose who can just control space with low strong at the right range and that's it. She can just sit there and you're now forced to deal with it or lose. Same with CvS2 pre-roll cancels with characters like Cammy.
With games like 3rd Strike and V there's an effort to weaken that through frame data (without Alpha 3's wholesale nerfing of hitboxes) makes A2 style poking a bit more risky. Both these games (3S and V) have medium and especially heavy normals that aren't as safe as they were in games like A2 and ST, at the same time however, combining them with a priority system hat encourages you to use them to beat out safer normals.
There's an old writeup about 3S footsies written by the Japanese that laments how stuff that's safe on block in SFII and Alpha are super unsafe and punishable in 3S.
http://www.geocities.co.jp/Playtown-Yoyo/5394/ashibarai/ashibarai.htm
