Past this, when the Icon wants to
Epic TR out of this iconic life, they would do so normally
by reaching level 30ish, but rather than the new incarnation being granted a past life based on this class, they would be granted a past life feat based on what icon they were, regardless whether or not they stuck with the suggested class route for their icon.
For example, a Bladeforged past life could grant something like "heart of the Forge" which would Give the subject 20%healing amplification to Repair spells (meaning that even a fleshy could benefit) and also stacks like the Paladin past life feat.
And then a selectable past life feat could be the repair spell as an SLA.
Something like this would certainly motivate people to buy and play as icons, and not break the game by giving players easy ways to farm Paladin and cleric etc. past lives; especially if they were a requirement for the completionist feat (only throwing that out there to be fair).