Looks like it could find a place in a trick room team, especially in Doubles.
To be honest, I'm glad it's not that bulky because when you Eviolite, I find it highly unlikely Cursola would be preferred over Corsola. Just look at Blissey or Dusknoir, all of them almost outclassed by their pre-evolution.
Also, its special defense isn't bad at all, but its attack stat is a waste.
As for Coalossal...
I had HIGH hopes for it because Fire/Rock is such a good offensive type. It could have a place in a Trick Room team, especially in doubles with something like Eruption, etc. Unless it gets some op ability like Huge Power, I don't see why anyone would use it. Good grief.