Rather than having all the LP you've earned calculated using your trad/change slider at the moment of death, I propose that the amount of LP stored is calculated at the moment it's earned. Thus, if you are full tradition when you gain fifty points of LP, then gain annother hundred points when centered, and then two hundred points a full change and then die, you gain 50 from the first LP, 50 from the second, and nothing (or perhaps a small percentage) from the third.
Thus, while you can't "lock in" LP gained by having a high change and then switching to trad, you can spend some time with high trad and then switch to change without fear of loosing your investment.
Presumably, LP earned from reincarnating, having already been devalued, would no longer decrease. If you have a character that inherited 2000 LP, no matter how he dies, the next one will also get that LP. Thus, you need never lose everything to drowning/foxes/trolls/wind/etc. , particularly if you've invested in some work with high tradition.
I'm not entirely sold on the idea myself, but I figure I ought to throw it out there.