The notion of "first strike advantage" seems problematic to me, since it means equal power fleets are not actually equally matched -- sufficiently powerful first strikes can wipe out a huge portion of the defending fleet in the alpha strike, crippling them for the remaineder of the battle.

If first strike advantage has to exist, I would propose that it not be universal. For instance, if you are at war with someone, conceptually one would expect that your fleets are on "high alert" for attack and could not be surprised in that way. Alternatively, you could imagine only giving the defending fleet the 2x DEF bonus to offset the huge advantage of first strike a bit (or maybe you could explicitly put fleets in to a "defensive posture" as an offset).

Naturally, this leaves open the possibility of cloaked ships always getting first strike when attacking from cloaked status. Makes sense, right?

Generally, I feel like this first strike stuff, and the ridiculous power of colonies, etc., is making combat really unintuitive. Between all the different ship and orbital combinations, and these mechanics (and the bugs around them) it is impossible to understand what is an appropriate defensive strategy against any given attacker. I wish it was all a bit simpler.