I fight high-end bounties, Diktat and Hegemony fleets. My fleet has maxed officers but not that many capital ships. A Heron, some Broadswords, Thunders, Daggers and Xyphos evenly split. It was more of a struggle mid-game, and I did notice occasionally that a Wasp or Gladius wing would run out of replacements during combat, but even then no wing was ever removed from a lack of deck space. If your stuff is dying too quickly, maybe you're letting it run into nasty PD? I usually spread fighters out a bit, have them take as many map points as it's feasible. The +Armor skill is also essential as it buffs fighters also.
It's probably gotten a little harder for fighters since officers were introduced, but in various fighter / carrier discussions in the past it was generally the consensus that a flight deck can manage 4-5 wings.
Re: Venture. Yep, the civilian-grade hull and speed have unfortunately made this cruiser even less attractive. And it doesn't have to be that bad. It's certainly a tough nut, and I never thought of it as a civilian craft. So a 'back to the roots' military Venture would be pretty cool.