I only played WW2OL for a little while. I thought the fade in/ fade out was way too long compared to RL.
You do need to look longer to see detail, but I thought they overdid it.
As far as a glance, within reasonable range I think you can get the basic necessary info with a glance. Stuff like Friend/Foe and aspect for sure anyway.
Yes, you can tell a multi from a single a long ways away. Much farther than we can in AH, IMO. It's the pixel limit thing, I guess.
You have the problem of a small dot being a distant bomber or perhaps a much closer fighter in RL too. They're both just dots. However, in RL, they gain detail at much farther ranges than dots in AH.
Night viz is very restricted unless there's some sort of illumination. WX is the same; clouds, fog and such can reduce your viz to the end of your radome. Nothing like flying welded wing, hitting some weather on an approach and totally losing lead in the goo... knowing you were about 2 feet off his wingtip when last you saw him.