I wouldn't get a ninja solely for ranked unless you have a very particular build in mind - and only if your power was considered high for your server. There are a bunch of new ninjas released, and likely to be more soon down the road - so it never hurts to save. Playboy Sasuke isn't really end-game material anyways.

I wouldn't put him on that team you have even if I had the choice. Mei, Mabui, Azure and GNW tenten is pretty meta right now, and anything you'd gain from sasuke would override the synergy they'd have from slotting out someone else.