What are the downsides of CoC builds?

So i just made a DW CoC char with wands, nothing fancy just with stuff i had (medicore at best) and i was doing some test runs and oh boy, the monsters are not just dying like they'll usually die so nope they'll simply disappear after a short visual mambo jambo.

What are the downsides of such a Coc build? Is there anything i didn't take in account beside elemental reflect (goes ofc. for all elemental builds)? Or is it simply just OP and that's it?

1/ Party hate them
2/ PC hate them
3/ GGG hate them
4/ They hate themself

For reflect it's worse than other casters because you usually have multiple elements, you already have 2 gems in your 5/6l for Coc + trigger, eventually another one for GMP, so that leaves very few for life leech.

Then corrupting blood hurts a lot as you have a shitload of hits and usually not so much leech (or at least not until after your spell proc), although should be better with 1.3.1 and immunity flasks.

Finally you need accuracy, crit for both attacks and spells, and spell/elemental damage, usually you don't need them all at once. Only stuff you don't need is mana. Doesn't leave so much for survivability.

But for those small drawbacks you get for sure lots of punch.

And lag... desync too... and lag...