The worst part about survival is that it's too high stakes. Time/Potential Time Wasted vs. Currency Earned. Even on normal survival I've had the AI go nuts on the last battle 2-3 times in a row. And you're just fucked and all your time is wasted. You can't practice against the AI, you can't get better against the AI, you can't even learn cheese strats. You're bounced out and have to start over. It fucking sucks.
It would be different if you didn't have to fight so many opponents but hell survival is 100 fucking fights? And the AI can just go god mode anywhere between fight 80 to 100? It's insane. The number of fights, or the difficulty curve, or the mechanics need to be seriously re-worked. The biggest change I would like to see is being about to continue survival for a smaller reward even if you lose. Like drop the FM to 100 or something. Just give people a chance to learn the ridiculous AI or feel some sense of accomplishment.
The way survival is now it's just not worth playing.
Arcade would be a completely different experience. You'd get to continue after losses, you'd have brief narrative moments, a reward in a short story-style ending and the feeling of accomplishment from being able to complete a goddamn mode. It could track scores and times so you'd have a reason to replay it. It would absolutely add value to the total package.