Actually, most US carrier aircraft need an "Expert" bonus like they need a hole in the head. It just adds insult to injury with the already grossly undercost Essex class carriers. (They should be five points higher). Anyway, Flag 2 and one expert seems like enough to me. I still think a cost of 28 appropriate. Pay a little if you want that Flag 2 on a super carrier! Adding Installation Strike is neither here nor there to me. It has little to no bearing on cost/value so I don't care if it is on the card or not. If adding Installation Strike makes people more comfortable with a 28 point cost then I say add it. I really hate to see another 26/27 point Essex class. They are just plain wrong IMO.
Hancock is long hulled essex (something we dont yet have) that has the history to give it a desirable ability in a game sense.
Not every single aspect of a ships history needs to be represented on a card. In fact doing so creates poorly focused cards. Airfield strike doesnt do anything that the USN has any difficulty doing without it.
Since Experts are intrinsic to a carrier Im inclined to give it both expert bomber abilities at the expense of EDF simply because axis aircraft are fractionally more fragile and over the course of a game that one AA dice adds up.
And then cost it for its value in isolation. The cost gradings arent detailed enough to account for outliers high or low