My Changes to Super Powers
Personally, I find flaws in many of the superpowers. My main peeve is that many powers don't gain additional perks per level. I feel that people should see definite concrete advantages going up in all of their abilities. Perhaps having a spell do set damage is acceptable, even desirable. But for superpowers, I believe that there is little excuse for no perks per level. These are additions I have considered. This is based off of the Revised Second Edition.
Create Forcefield: Add 100 S.D.C./M.D.C. per three levels, and add 1D6 to damage per five levels (meaning at level five it does 3D6, level ten 4D6, level 15 5D6).
Growth: I'd say that it's fine, but add an additional 2 feet per level, meaning a 15th level character can get 30 feet additional! This is a nice way of rewarding long-time players as well as making Growth better for people with low P.E.
Karmic Attack: I'd personally add a +2 to save vs. Horror Factor, a +4 to disarm, and a +2 to entangle. In addition, allow an automatic dodge. This power is plenty strong enough, though. You might also want to add a few bonuses for every level; how about additional skills (as long as they are humanitarian in nature), an additional +1 to a bonus here and there, or maybe even automatic or flawless rolls with punch/fall/impact!
Multiple Beings: I see a flaw in the two types of ways you can create duplicates. One has you get a new duplicate every level, but they are all one level lower than you. The other sees you get one every two levels, but they are the same level as you. Now, let's see the consequences of this (A is the first type, B is the second type I mentioned):
As you can see through careful examination of the list, I'd say that A has an enormous advantage. A always has double the clones with one level less in power. Unless you really need one level higher for some strange reason, I'd say A could beat B anyday. The game already makes sure that both of them can make one clone in the first 2 levels. Personally, I'd add an additional clone at 3rd, 7th and 9th level, raising the maximum clones for B to 10. I'd say that relatively minor modification should even out the playing field. Of course, in some situations (like being a Mystic or Warlock PC, in which case you can only use new spells every new level), this is entirely fair.