Cor can definitely solo, although I wouldn't recommend only shooting when soloing on cor. Cor is not in the same class as bst or pup because bst and pup can't buff (marginally smn because smn buffs can be nifty). Some of the new NMs in Escha have such high evasion that you need hunters roll, madrigals, precision and torpor from a geo, and you'll still miss! If they decided to give us a third roll that would be cool but cor is already a very useful job.