how about this:

Add a store item, that will bank XP after you hit level 20, up to a cap that will let you bank enough to hit lvl 12 on whatever your next life will be.

Make it cost a lot, say 5k TP, to offset the lose from TP that you wont spend leveling up.

Lvl 12 makes it on the one hand not an "I win" button - you can't bank your XP back to lvl 20, but lets you get right back into the fun with a second level PRE, and your GS weapons.

I am not one to talk, as I am only on my first life, and this might upset people who TR'd the long way.

Just an idea.