As I see it, there are distinct advantages to both approaches:
1) If we do "Defenders", then you have pilots that level up, aided by nameless (but also levelling) wingmen. This focuses on indivual units for players, which preserves the HotAC feeling.
2) If we do "Squadrons", then you have a more strategic element to it and the tactics are more important, but you lose the HotAC feeling.
None of those two is better than the other, but I feel we should reach a consensus about the direction at some point and start working specifics. I have a preference for option 1), and I'd argue to combine it with a mobile base that can also be upgraded (Gozanti). Totally selflessly, of course.
I've stayed out of this discussion so far but have given a lot of thought to how I would handle VotAC, and this is how I would do it:
•Everyone starts out with two TIEs, a leader and a wingman. You determine the movement/actions for all your own ships. None of this AI wingman nonsense- AI is for the enemy.
•As you progress through the campaign, you can upgrade either or both of your TIEs, the one with the highest PS is your wing leader, AND/OR you can spend XP to add another academy TIE to your squad, up to a max of 4 ships per squad. Each TIE can be upgraded individually.
• (optionally) when a ship is destroyed, rather than "ejecting" like on HotAC, the mighty Empire sends you a "replacement" pilot. Roll dice depending on where the destroyed ship was ranked in the squad. If you roll well you're replacement will match the ship and upgrades that was destroyed. If you roll poorly then the replacement will match the ship/upgrade of one of your lower ranked squad members (obviously this needs a lot of testing, which I have not yet done).
A system such as this would let each individual player answer the squad vs ace question for himself. Want an Imperial Ace? Spend all your XP on upgrading one ship and maybe put a little bit into your lone wingman. Want more of a squad feel? Spend your XP to add more TIEs to your squad and spread upgrades amongst your ships relatively evenly.
There is more to it but that's the gist of what I came up with.