If you've already 5 starred kurenai and done all of kurenais skill breaks, then sure get sakura GNW. But Kurenai is what you should be spending those arena points on.

yes she is from ranked shop, she isn't from arena shop, but only if your refinements are level 4 or higher, so if you don't need anymore basic refinement runes, otherwise you should focus first on them.

If you are looking for a good healer, I say get her. She is pretty good in my opinion until you get to the really high levels.

I only come here for Pikachu with Pokky :3

Get sailor sakura. Actually all sakura is good. Sakura SB for me is the best at the moment. Can mystery heal round 1 and round 2. Then again gnw is still good but i like the scaling damage of sailor sakura and she c*so tank. The area attack of sailor sakura is very good to be paired to poison tai(cause you want water main) which I think the best standard among the sakuras.