kitcik
Adventurer
Unfortunately, it wouldn't. "Experience is a river" and all that. I.e., once you're a level behind, you start earning XP faster than your colleagues, so you will eventually catch up again. On occasion, you may even overtake them by a significant margin: if you're close to leveling up and a major fight provides lots of XP, you'll get many more than your teammates and may end up higher in XP than them. Happened in my group just recently...
Yes, you're right, my bad.
I am hopeful about the interrupt thing discussed above as I think this is the best way to nerf casters (loved it in 1E), but I just haven't been able to build an elegant (i.e. not too complex or not too many ripple effects) mechanic to make it work in 3E. Hopefully, brighter minds will prevail.