Thoughts on Wanda?

I'm interested in pulling Wanda with her free skin coming out, but I'd have to choose between her E3 and Arachne's E3.

Wanda seems like a very arithmetica- heavy character, so she wants to be a central player with support characters. However, she seems to want to just sit there and build up stacks of her passive so she can get counter and then continue to sit there while enemies kill themselves.

Does Wanda do more than that? It seems you'd just get chipped down over time since she is all about getting attacked and slowly ramping.

For team comps, would you build her with more counter synergy using, like, Faint or Pandia? Or should you go all in on tanking and healing and letting the counter be your main dps?

Is there a meta "Wanda Team?" I have her wheel with a few merges. Is it BiS or is another wheel stronger?