Power Specializing Revisited

Rob replied to a post I made a couple months back basically asking, "what's wrong with taking the same power multiple times?" and I think it's worth reposting. My rationale was why not let a character take a power again upon the opening of the next power in that set. He's essentially taking a "lesser" power than the one that just opened up, so game balance -theoretically- wouldn't be compromised. Rob answered with this:

"Actually I think I know this one. Sol has his AOE blast that does about 45 [damage] on average to a large number of villians, [with a] recharge time of 5 sec. If I took it 3 times i could just cycle through it doing huge damage al the time to a giant area, needless to say i have crocked my end recovery to the point that I never lose end anymore. But hey if they let me take it 3 times then let me respec."

But I think my logic still holds. I'll assume he's talking about the "Rain of Fire" blaster power. You can't take this power initially until level 6. You would have had to buy powers normally up to that point, not just start out with RoF and begin taking multiples after that. Theoretically, you wouldn't be able to take it a 2nd time until level 8, a 3rd time until level 12, or a 4th time until level 18. In the meantime, you're chosing to pass up supposedly more powerful powers to take RoF again, and the things still have to be slotted to be particularly useful vs equivelant level villains. Personally, I think efficient slotting would be rough, and specializing in anything, while it makes you superior in some aspects, makes you weaker and/or more vulnerable in others. It should be a significant trade-off. Maybe it would have to work so that you can only take a power a 2nd time that is 2 steps "weaker" ... or 3. My initial thought, too, was "that's unbalancing," but thinking beyond the first kneejerk reaction, I'm just not sure it is. Again, I haven't tried to balance this beyond the initial thinking, but I'll bet someone at Cryptic has. This is one of those times I wish I had a designer's ear.

....no, not like that.