Will Cloyster be a good counter to future raid bosses?

I have used Cloyster but Lapras, Piloswine, and even Jynx have it beat as a Dragonite counter. Piloswine and Jynx have Avalanche available to them. Also, Articuno will be around soon and will also be better than Cloyster in this regard.

Cloyster is really good vs dragonite, can bring a 3000 cp one down 3 times without healing (and dodging charge moves ofcourse). have 2 around 2000 CP (ic/b and ic/av) i prefer blizzard because i can kill a dragonite before a charge move if well timed.

He will be a Supreme Counter.

Jynx will kill Dragonite really fast (must dodge or you are toast)
Cloyster will kill Dragonite pretty fast (can take a hit or two, but will die without some dodging)
Lapras and Piloswine will kill Dragonite and are a little tanky to make up for the lack of speed.
Haven't used Dewgong or Sneasel, from what I've read dewgong is a mini-lapras but not as good. Sneasel just seems like a small jynx and would get toasted faster (but no experience here).

My personal favorite is cloyter, he's fast but can take a hit if you don't get all your dodges right.

I have a 1945 Cloyster, seems to be great for taking down stuff that's not super effective against it when it comes to raid bosses. It somehow can deal a lot of damage even to Weezing, although I'd need several of these to take that one out. Did more damage than my ground attackers. Avalanche is pretty easy to load if you need lots of damage done fast.