Maybe. It has been possible (But highly dependent upon the game) to find more than one exploit in a single game's saved data. Thing is, if you're looking for another one, chances are:
A) People have already looked
B) It's unlikely to be another buffer overflow exploit
But good news, Wololo's got a guide up on his site somewhere. Search around for it. I've found crashes. Haven't really gone further than that though. You'll have to settle for a Usermode exploit for now, provided you do find one, but who knows? Maybe one of the devs (if possible - it's been possible in the past, albeit unlikely now) will find a way to port eCFW to the (your?) newest-future-exploit.
Hell I think mine's still on 2.x. I've got emulators and Isos. Love it. But I've got another Vita with the highest ofw. If I had to choose, I'd choose my legit Vita. I've played the hell out of my PSP. However, having the Vita on a lower firmware for... well... a LONG time, could be a plus. Many people do this with their systems. If a vulnerability is found, leading to native Vita hacking, then you'll probably want to be on a lower firmware.