All of what you said depends on the person/player, Personally i'm a ranged-type-o-person, So i prefer ranged classes, namely hunters. Or casters.
Overall, I'd say hunters, Warlocks, and Elemental shaman, i enjoy the most. And warriors, before they lobotomized them.
As for battlegrounds, Like all brackets, you'll get some good, some bad, you know how that goes. Depending on what class(es) you play, May really need to avoid mages. Queue times range from instant to 10 Minutes, usually. Alliance/Horde win/loss difference isn't largely noticeable, Of course, when guilds run full 10/15 premades, That'll swing how a battleground goes, But all in all, battlegrounds are usually a blast.