Aside from the obvious fact that it sets your first life off with basically a free Stone of XP, I kinda hope they decide to keep Iconics permanently separate from the TR system.
If they do, then they can officially design Iconics to be "endgame ready" without needing multiple PLs, as many current builds do. Make up for the lost active/passive PLs with more powerful abilities right away. Iconics could be a nice 'change of pace' character for people who've already been through the TR meatgrinder with one character already.
And I'm also afraid that if you can TR them, you can TR INTO them, and obviously then 80% of the characters in Epic are all going to be variations on "1 Iconic/19 Build X" for all the extra skills and abilities.
Plus, if Iconics ARE ever made TR-compatible, then all you Completionists will have to go out and buy, and play, all 4 Iconics to re-qualify...