OK, another idea:
Those with extra Epic Destiny XP get to put it into a Epic Experience Bank at the first Epic TR (and only the first Epic TR.) It can only be used on Epic XP (and thus ED's) after a TR and it must persist through a few TR cycles. Assuming we will need about 5M XP to cap Level 28 [from Level 20] once they adjust the XP scales, we could use that Epic XP bank to bang out L20-28 3 or 4 times rapidly and keep TRing. This would give the players a decent return on their TIME, and give the Devs a mechanism to implement the loss of EDXP on TR.
That would work out to a 3:1 or 4:1 rate in DDO's favor, but still grants us 6 PL's (3 Heroic / 3 Epic) in the process at the 3:1 rate.