If your main goal is to just level to 80 and experience that journey, it’s perfectly viable and doable even this late into WotLK. The world is open for you, and the dungeon finder is somewhat active during normal hours. My experience is that people running low level content are relatively considerate towards players starting out.
Anything related to level 80 endgame though, I wouldn’t bother at this point as a fresh player, to be completely honest. The barrier to entry is ridiculously high, you need either a couple of already well established friends that can carry you, or A LOT of gold, think 100k and beyond. Serious guilds will probably not consider anyone starting out, and raid pugs are mostly interested in well established raiders alts.
You can try your luck in level 80 5 man dungeons though (there’s this extended version of heroic dungeons called Gamma). But you should know people running these are not as considerate towards a fresh player starting out. So it’s a rather toxic place to be in, especially for anyone that isn’t an overgeared minmax tryhard.
I rarely PvP at all in this game anymore. But you should know that battlegrounds are basically a bot infested mess, so if that’s not your cup of tea you should probably avoid them. Also prepare to be oneshot by every Shadowmourne wielding warrior the moment you enter a battleground, the power difference between low gear and high end gear is enormous this late into the expansion.
So to sum it up, you CAN start WotLK classic and level up to 80. But you will be lightyears behind everyone else, and it will be very difficult, if not impossible, to catch up when you’re at max level. I’d say the newly released Season of Discovery is a more friendly environment for a player starting out.
Edit: As for what faction to choose. It depends what you value. The most active community in EU is probably Gehennas horde, if you prefer to have a large community of players around you. But my experience is also that the larger the realm, the more tryhard and toxic the general vibe is. So if you value smaller community, but a bit more relaxed environment, you should probably look into a server like Mograine horde. Alliance counterpart would be Firemaw for the big realm, and a realm like Earthshaker for a slightly smaller, but still active, community.
Which faction you choose won’t matter that much performance-wise. There’s a bias towards the top PvP’ers picking alliance due to humans essentially getting a free pvp trinket via racial. But this difference will be minimal in casual pvp like battlegrounds and low rated arena games. So just play what you enjoy, I’d say.
