Hello, Yes EU I think has increasingly unbalanced battlegrounds but I can give you a general overview.
EU is a nice friendly server with (many noobs joining Bgs) and a fair amount of 24's
-The deal is in EU the side which queues the fast personally I can say horde at average ~3mins, when ally can go up to about ~10min or less. This applies to dungeons as well.
-Horde wins approximately 80% of the time in WSG and the same applies to AB.
-If you looking for a stronger toon, gear wise do ally (Stockade) especially AGI users and Holypala. If you going for fast looms and a fair amount of 24 Spriests join horde.
-Some servers I suggest for the community of twinking would be Draenor and Aggrammar, looking for fast AGN go a Rppvp or an RP server, preferably Ravenholdt or Sporreggar.
Personally I would do both, Ally has a friendlier community because it is small and concentrated and Horde you can get a bunch of douchebags and shout at you for being a noob (sometimes), but you win more bgs.
Obviously my post is completely biased because I used to play Horde A LOT but I've got my fair share of ally knowledge enjoy!
P.S If you could tell me what server you will be at I will be fine to help you with 'stuff' Agm and what not, for the rest, DONT JOIN FULL SERVERS

!!!