Hmm. Seems a little too good for 4. If the ability to pick targets is always on, it should have only have A1/S1/L1.
At 4, its the same price as a sub with its torpedo ability. Of course, because the tactical bomber is more flexible, i.e. can attack land and air and has more movement points, it shouldn’t have the sub’s pre-emptive strike ability: it should have to survive the ‘Attack Air Units’ phase before it drops its payload. Even then, you might want to say that the targeting ability only works when escorting fighters are present on a 1:1 ratio (kind of makes sense; without cover, they’d just have to drop their bombs on the nearest ship without being too picky, and beat their way back to the carrier).
A double-striking, targeting tactical bomber for 4 would be a nightmare, knocking out both fighters and bombers for purchasing points. On their own, either of the abilities are inoffensive, but together they would be nuts; especially remembering that Victory Points are directly derivable from sinking Capital Ships.
As for tanks, I agree that they don’t add a whole lot to this particular game. Nevertheless, I think that they would be viable units for other games that employ this great system (which I sincerely hope someone does).