>>39716068Zero chance of a community day for any mon that already has its shiny released.
There's no other reason to wait, even if poliwhirl were pvp relevant (it's not) you usually want specifically low atk iv for pvp. Read up on pvp using Google if that's what you're wondering about.
Enjoy whichever evolution you choose. Neither are great. Flexing traded mon, has some possibly useful pvp legacy moves.