When at level cap you already gain a 25% gold boost, and I'm not much for gaining back the exp because then there would be no point in having a level cap at all, people would just reach the new cap in no time and new players won't ever be able to catch up to older players.
Edit:
Nevermind, didn't read well what you were saying. You want to transfer the Exp boost into a gold boost when at cap, I would be ok with that but probably with a lower %.
Edit:
Nevermind, didn't read well what you were saying. You want to transfer the Exp boost into a gold boost when at cap, I would be ok with that but probably with a lower %.