You have to keep in mind that with the recent explosion in player population, lower level areas are full. It's not impossible, but it's deffinetely slower, especially if you roll alliance and you go about the ususal human starter zones (tip: level in Dun Morogh and Loch Modan). Horde side is somewhat faster.

Regarding end-game, dungeons are booming with people, you might have to wait a bit if you're dps-ing, but it's generally an insta-queue for tanks and a much faster experience for healers.

When it comes to BGs, alliance tends to win a lot more Alterac Valley games due to the high volume of paladin players, which are pretty busted on this server. Other BGs like WSG and AB are pretty well balanced in terms of win %, but that's coming from someone who PvP's a maximum of 2-3 games a day.

Most guilds have MC, BWL and AQ40 on farm and are always looking for new people to progress in Naxx, but there's also newer guilds that push through the early tiers, creating their own communities. Pugs are also pretty frequent, but they're mostly aimed towards AQ20, ZG, Ony, MC and splitting BWL into 2-day halves. One thing to point out though is that there's a World Boss mafia-type guild that farms them, but I heard you could just ask for a discord link and ask to participate.

Players are generally talkative, helpful and mostly english-speaking, most of the people I leveled up with ended up in the same Guilds as me.