For chits and giggles I decided to go sans-icons for a month in the AvA when it was still called the CT. I gave it up after a week. No icons was do-able, but only just. I had to get within 200-300 yds of an aircraft to get an ID that I could be reasonably sure of before pulling the trigger and I made a bunch of dry runs on friendlies I figured could be the oppo as a result. The opposite happened too - I got nailed by oppo I'd figured were most likely friendly - a lot. My SA had to be turned on and highly tuned every time the gear went into the wells or I was a flying target, and that made suspense and surprise a real factor in the game. I found myself pretty much useless flying by myself though - spotting aircraft, even up fairly close, was next to impossible when they were lower than me so I wound up winging with any friendly I could find. Spotting aircraft wasn't much easier co-alt either and once engaged with them it was incredibly difficult to keep track of who was who if there was more than just me and my target in the fight. I definitely wouldn't recommend it for players with a low-end system.
It was probably the most immersive and adrenaline-charged time I've ever had playing AH. But it did raise the level of difficulty to play AH by a huge factor. IMO, if it was possible (and it isn't), it would be a blast to play a snapshot every once in awhile with enforced friendly-only icons.
cheers,
asw