I think it should be noted that a Pokemon that uses Double Team isn't creating clones: it's moving quickly to a set of locations such that it generates afterimages, and the more locations that are present in the set the more energy the Pokemon expends. Because of that, multi-target attacks with a limited number of targets should not guarantee a hit; after all, the Pokemon has only a one in whatever the number of images you've created chance to be at any one of those locations. To follow that up, all multi-target attacks that hit an infinite number of targets should still destroy the clones, ignoring the stupid immunity cases. Also, all damaging attacks obviously destroy other clones upon hitting the correct location. I believe these conditions do not exclude friendly fire, because let's be honest – your ally isn't going to be sure which one is you at any given time.
Then, the only cases remaining to tackle are a) residual damage and b) non-damaging attacks.
Residual damage should not destroy clones. True: it's a global effect that hits every location and therefore it may be considered as a multi-target attack that hits infinite targets. However, for the sake of consistency, we can't treat weather damage differently from status damage (i.e. poison and burn). And the "clones can copy pain gesture" (not singling you out tavok, it's just the first thing I saw) argument is erroneous; the clones do not copy gestures, but rather each "clone" is that Pokemon a fraction of the time, and therefore each "clone" quite obviously has the same appearance as "the real Pokemon." If a Pokemon that sustains a burn can move around quickly just fine, there's no reason a Pokemon that's getting pelted by hailstones can't. Why can't we just make all residual damage destroy clones, then? Simply put, I don't think it's enough damage (both actual and flavor) to justify destroying clones. While weather damage can sometimes do more than actual attacks, that's extremely rare (maybe if Incinerate is your only multi-target attack???) and even then an "arc of flame" sounds like it'll do more damage than "hailstones" and therefore have a higher chance of knocking the Pokemon out of concentration long enough that it can't perform the quick movements necessary for Double Team.
Non-damaging attacks are slightly trickier, in my opinion. I think that currently they do break clones, but applying the same logic as above leads to the conclusion that they shouldn't destroy clones, since, well, wagging your tail at an enemy is going to do less to disable them from moving around than hailstones will. As much as I'd like them to destroy clones (personal bias go!) consistency reigns supreme, unless this change really breaks Double Team which I'd highly doubt. I don't particularly mind either way how this ends up going, though.
At the end of the day, Double Team is simply a high-risk high-reward move that is accessible to virtually every Pokemon. It costs a rather impressive amount of energy to use, and the result is up in the air, which is one of the worst things that you may have to deal with when ordering second. Oh, and you definitely don't want to use it going first. Can it completely screw over the person that ordered before you? Yes. Can it backfire, making you waste 16 EN and an action? Absolutely. I don't think Double Team is overpowered; it's excellent in select scenarios, and there's no need to make its effective situations even rarer.
