I'm reading heavenly into all the options in the Cortex SRD. My impressions part 1 is here. One of the things that jumps out at me is the ability to mix and match options. Prime looks to be very modular game allows for cherry picking of mechanics.
For example something I think would be great for lower level heroic games, like street level supers is mix heroic dice with doom pool. Allow the players to bank dice specifically to do things better (add to the total of rolls). While the GM gets dice to make the bad guys a bigger threat, both without specifically raising the power level of the game. More or less normal people (although possibly highly skilled) pulling off heroic feats when they need them.
Characters turning a great success in one area into greater success in another, which I love. It feels to me like story momentum.
I came up with a variant as well, allow player to bank spoilers as hero dice, each banked spoiler becomes a banked d6 hero dice. GMs can set a limit to the number of hero dice that can be banked from a single roll if they fear the players would gain hero dice too fast.
I like the idea that it doesn't cost plot points when banking hero dice, it gives the player a way to take advantage of spoilers even when they are out of plot points. Then gives them (another) motivation to play their flaws and negative distinctions to come up with plot points to use the hero dice.