Rarely do I have to wait more than 5 minutes to be able to join my squad in the right arena. I just logged on and caps on Orange were at 105/100. Started the clock, took 3 minutes before I was able to log in. If I wanted instant action I could have jumped in blue, but if I did want to fly with guys in Orange, I had to put myself through 3 agonizing minutes of patience. Caps can be an annoyance when you get on, but I think it's been made very clear that they are here for a reason, and they're not leaving.
Also, checked the people on. 74% were in-flight at the time I checked. Obviously the other 26% weren't all afk, they might have just been checking the map, getting ready to launch, etc. We can't know who was actually afk and who wasn't but I think your 50% number is obviously an exaggeration.
I just don't think it's a big problem, not one that warrants any changes.