1. Atleast 40% of the in-game community can speak english to an extent. Does not apply to battlegrounds, as people don't follow objectives anyways.
2.Major bugs? Not at all. Every class is playable with a very few exceptions( feral bleeds, demonology mastery but idk if fixed already).There's a few random bugs that might appear after a month or so but they get fixed pretty fast.
3. Used to be at 6k peaks. Currently in the evening there are around 4-5k people on x100. Fun should be 3k+
4. Faction balance doesn't matter. Good players are at alliance but horde is populated. Instant bg ques for horde, max 5-10min for alliance.
5. I'd suggest x100 because fun has some HC SoO(last tier) items for conquest and a lot of people get them. MoP PvE is disabled in Fun realm
6. No broken classes. Currently as i said all classes are fully playable with some mechanic bugs and warriors having a little bit of a damage increase(crucial). Healers are fine as far as I know.
P.s. Green fire works, legendary questline is getting fixed, SoO and TOT works