You may want to wait for that announced Summer Solstice event. No details yet.
Speculation is rife. That it may be another Black Friday Summon Extravaganza portal : No S1. No costumes.
Read this thread, from this post onwards.
I wouldn’t try for AR till new heroes are in. May 30 is the earliest.
As for S4, unless you want that featured hero…, I would divert my funds to newer heroes.