u don't want a mk3 cyrax, trust me lol
cyrax isn't that bad, is just he's hard to control at hi levels. I'd just make the bombs easier to pull off and like TRS said, a better air throw. The tlpt is useless, I think it could be faster.
for sheeva, hmm faster ground stomp would be cool and the ability to relaunch..
Invented and animation hacked by me, programmed into MUGEN by Konqrr. Of course this is just a preliminary concept of what it'd be like. It'd have recovery frames and slightly different properties. For instance, the action the opponent would take would be a front flip like Reptile Forceball. It could act as a two hit if used as anti air, so the knee on the way up would hit and automatically allow the stomp part to connect. If this happens it should cause damage protection on the knee lift part, this would allow for a decent juggle scenario for Sheeva, stomp, HPHP, RH, ground stomp, would be over 50%.
Aside from that, she would need no DP on her throw like in MK3, and also a fix to her stuck ducking issue when being hit while blocking.
For Cyrax, definitely no damage protection on his throw, and normal damage for his throw on top of that, so that would be like MK3. This would mean throw, aaLP, net, aaHPHP, air throw would be pretty big damage, between 55 and 60%. Teleport should definitely have a little less recovery time and he should appear a little further away.
I was also thinking about a controlled release bomb, maybe a different color than his normal bomb, so you could do maybe hold LP FF, HP that would throw a bomb that detonates as soon as it stops bouncing, and holding HP after that would keep the bomb from detonating for a few seconds until you release or it goes off on it's own. Just something interesting that wouldn't require too much adding and more of just changing properties.
For cyrax I'd say give him a different air throw. The one he has can't be used practically all that much. A pop up combo would be pretty neat too. Think of it...you could pop them up then net them. Would help his combo potential quite a bit. Shocks bomb idea would be pretty badass too.