I'll play devil's advocate on this one a little.

What if instead of increasing the multiplier for each job to 60, then why not do it by role instead. It would be an interesting way to spice up 4 mans at cap if I could have more jobs at 60 and this whole thing where 2-3 days of lvling to lvl a job is only if you have several hours of playtime a day. I would enjoy being able to casually lvl up jobs and not have to give up other parts of the games that I enjoy.

So, DoW and DoM only, being able to speed up the process of having more jobs available to run roulettes at 60 would be fun for me. I also understand that it has the potential to be game breaking, but not if it's done in a fair fashion. So, let's say I level PLD to 60 then I move to WAR. What I would propose is a 10% exp bonus on top of rested etc. Any job of a role after that would get an additional 5%. Since your simply learning how a job does the same role, then the learning curve is alot less steep.

The major problem I see with my own solution is that you would have to further seperate roles into melee DPS, caster DPS, and ranged DPS for this to work.