Well the chance of new server seems it might be a GoD version. (But i hope not)
Looking a bit in the past and current servers now, dominating ones are Hi5 (which are sh*t load of them now)
But in the past interlude/gf servers in my opinion had the best success.
I know lots of ppl might not agree with me but the way i would like to see the new server is smth low rate, oldschool, plus russian servers like rpg seems to get a great online number, until sh*t happens and it fails. Like for the first days it had 15k online, but i bet most of it were just dual boxes...
Recently, i've tried x1 interlude server, no dual box. Not bad server just not enough promotion, advertising so server is not very popular and known and online number is around 1000 (no dual box). So i think if server would be smth like interlude/gf x1 or w/e and most important No Dual Box, you might get good stable online number. And no fake online counter like 2000 real online players and 10.000 dual boxes..
Well its just my opinion, everybody has different thoughts, just thought maybe somebody might think the way i do too lol..
And as MadlyInLove said, english language would be a big advantage, since most of the servers are full of ppl from all around the world.
Once i've tried russian server, logged in, all shout chat and letters were in russian language, all shops in russian too. So i knew i wont be able to understand what is selling or buying what, or how to get a party at all lol (and its enough for me to know 3 languages already). So it's better just to leave right away.