You really are putting a lot of emphasis on BFGA2 in your analysis, but let me bring in some understanding of my own from the tabletop game. First of all, the Imperium is not a gunline fleet, it's the single largest fleet int he game and it has ships to support lots of different play styles. Want to load up on cobras and spam torpedoes across the board? Sure, you can do that. Lanceboats? They've got em. Ramming? Giant prows say go for it! The Eldar get 13 ships across all of the original BFG ruleset. 5 escorts, 7 cruisers, 1 battleship. 5 of those ships, all capitals, have launch bays, and two of them are specialist fleet flagships, while two others have them as an optional weapon vs the eldar's also excellent torpedoes. Only the Ecclipse class is called out as a specialist carrier design, and it's fluff is telling.
Rather than generalists, most of the Eldar fleet are specialists. Aurora cruisers are all torpedoes and lances, Solaris cruisers are all weapons batteries, and the Eclipse class are specialists in running up in your aft, dropping it's entire flight wing behind you, and then vanishing back into the mists while it's fighters and bombers claw your face off, maybe throwing in the occasional lance if it's funny. Eldar also have a 2+ against all ordinance, so fighters cannot pen holofields. I mean, I guess they can but the game doesn't offer better defenses than that. All the canon eldar ships have no PD at all, because Holofields are just that good. In that spirit, one or two random hangers squeezed into ships that are already badly hurting for their system slots is out of the question. You can't fit a a hanger, 3 aetthersails, 1 plasma drive, 1 PD, holofields and both shields on a Clipper without compromising
You know what's the real weapon against strikecraft? The Helm. Eldar ships can move up to 50-60 cm per turn in BFG, but ork fighta-bombas and torpedo-bombas are only capable of 25 and 20 cm of movement respectively. If there's a big strikecraft squadron coming at you, turn away and run. If the eldar don't want to take a fight, they don't have to.
You'd have us instead put out nearly 1000 new fighters to add to our fleet. Even if these are stripped down bare-bones nothing-fighters that cost only 200 EP each, we're still talking about 194,400 EP of construction here, or 19 turns of 'the forge does nothing but build fighters with both actions every turn.'