We all have the enlarged option enabled. Thing is, that all other planes we've encountered in our BFM training is possible and even easy to see, but for some reason the MiG-21 is just as hard to spot as it was in 1.0.
We actually flew circles around an airfield, using the F10 map to check where the other one were supposed to be, for an eternity before we saw each other and then we lost sight soon after. However, when one of us jumped in a F-15, the other could see him right right away.
Had the same problem days earlier when our squadron was out flying, I was searching for my flight whom I'd lost sight off, for ages. The other squadrons A-10:s operating in the distance was easily seen without any effort, but I didn't see my formation until I ended up right behind them by pure chance.