I find that no one speaks English in battle chat. I relaize it's an EU/RU server, but still, does no one speak English natively here?

It's a russian game, 90+% of players are from Russia. Once you experience the imbalance, you'll understand why Europeans ran away from here.

Imbalance in nationality or actual classes?

Just have fun till you can I give you a tip - level up as slowly as you can (always max gold not exp after battle)