Obviously, I'm talking about those who play the standard advanced sensors, Genius, VI, Bomblet Nym. If you're currently playing Nym in some other configuration without Bomblet, more power to you, but obviously your build would be unaffected by this change.
I don't play Nym personally, but it feels like this might be a good change to diminish his OPness of both Nym and Bomblet Generator.
Regarding the card in isolation, for three points, Bomblets should not be as far ahead of seismics as they are - on average damage, a bomblet pays for itself if you drop more than one, and that's not hard to do. Dropping it down to one die would mean on average damage you'd have to drop three to be worth more than seismic, which seems about right. It means that Bomblet stops being autoinclude whee it's available and the alternative options are seismics or other reveal bombs, without rendering it irrelevant.
As far as the standard Nym combo goes, he suddenly becomes far less threatening, much more in line with where he ought to be. Your high agility aces (think Soontir, but also Inquisitor etc.) now can't catch a pair of unlucky bombs and be destroyed, now they need at least three (excluding the effects of crits I guess) and you need to be very unlucky - 5 or 6 is probably more realistic, and Nym should have died by then. Doesn't mean that Nym is completely useless - that area denial is still effective, but it's not an autowin any more - you need other damage dealing mechanisms to handle those lists as well.
Best part is, FFG could make this change without changing the printed cards, just the rules reference card, which they've been more willing to do in the past (see Phantom nerf).
Does this seem fair? Would it open up the meta a bit more if Nym was less dominant? And are there any other, better changes that could be made (short of stripping his EPT, which I agree shouldn't have been there in the first place but, Reddit FAQ notwithstanding, history has shown FFG is unwilling to do).