Yep. It'd amount to the same thing as 'XP is awarded at a diminishing rate' or as 'Advancement costs in XP increase with the total number of XP you have earned'.
I just think it'd be easier on people to frame it as this two types of points thing. You wouldn't have to figure out how much a stat increase is for you, the table would stay the same. If +votes are still used, you wouldn't want them to decrease in, eh, visible value. Because they're also a measure (not a great one, but hey) of how much fun you're creating for other players, and you might go 'fuck, what am I doing wrong?' if you can't see how many +votes you got (and it's a reasonable call to hide that info, as some games do) and your XP earnings drop.
I don't mean any slow transformation.
I'd base the rate on the individual character's XP total, but that's 'cause I'm thinking of slowing advancement, not about trying to keep all the PCs closer in power level. I don't think I want to do that, but I don't think it'd be a bad thing to do.