I'd prefer to see this combined with A Proposal for Additional Levels
(which I thought got mostly positive commentary) and say that at certain levels you stop getting XP for various things.
For instance at Monk (6 in the new system) you'd lose the 50% bonus for voting out, at Vicar (11 in the new system) you'd lose the bonus for signing in, and at Bishop (16 in the new system) you'd lose the bonus for voting on someone else. With tye's XP scheme only 36 users would lose the voting bonus, a few hundred would lose the login bonus, and more people would have the "vote-out" bonus than do now.
Yes, I know that you wanted a smaller change. But the real issue with a big change is not getting people to agree to it, or getting it implemented, it is agreeing which change to make.