I became quite effective with most all of the characters (Chaos was only usable since the CPU opponents were predictable and rouge leaves herself too open for playing against another human). By spamming the proper attacks (and some clever use of special moves I developed) I didn't need to bar Emerl for the people I played (all 2 of them -.-). I'd have to say Sonic, Shadow, Tails and Cream were all tied for my best characters, although Tails barely made it thanks to Chu^2 bomb spamability (locks anyone lacking Rouge's jump into repeated damage immediately overhead).
We ought to exchange interesting skill combos sometime. I've found several useful (as wellas unexpected) unexpected effects in my various play-throughs, like Rouge's dash combined with Tails' dash attack, which sends you soaring to the height limit of the map when used together (even with High Gravity Lv.2). Similarly, by using Gamma's dash with Rouge's dash attack, you could completely immobilize a foe for several seconds bu alternating directions during the multi-hit then easily chain the same effect after the foe is thrown. Lastly (of the ones I remember off the top of my head), spamming cream's air attack can keep you almost indefinitely suspended in the air when coupled with Rouge's jump and Low Gravity Lv.2 (at the same time KOing all computer opponents as they jump up to try to hit you, which also gives a slight altitude increase on each hit).
Sorry for the text wall. I tend to explain strategies in full detail, especially when it's something I enjoy.