Exactly that. While it's not always the case, but quite a few of super/clantesters are good or very good players, who know a lot of stuff about how the game works and can use that knowledge.

Well, it's still WiP so the stats may be pretty different when the ship will be available.

IMHO: Venezia is not so OP in its current state and you can probably find a replay with almost any ship which did mega-super good in one particular fight...

Nah, it's a good ship but not an excellent one or OP.