I think that it would be a great idea to make 2 versions of each iconic: a 1st lvl, and a 15th lvl one. The 15th lvl still must get to 30 before reincarnating, but gets to pick all the classes from first level. The 1st lvl one starts at 1st, must go to 20 (therefore only gets the basic past life, not the iconic), and the first level is the fixed class (therefore still preserving Turbine's sales of +1 hearts!)...
IMO, this is important because the four we have now, have different racial trees, making them as much 'subraces' as drow is for elf. I imagine if drow were added now instead of way back, they'd be an iconic with ranger, maybe... But, we have the ability to make 1st lvl ones, which is awesome! Turbine could even whip up an iconic version of the drow if they wanted. This would double the racial potential, keep old sales income and add more even... Not screw up balance of the game, and give players a ton new build options.