One can think of some orchestras as having distinct personalities too, like the Philadelphia Orchestra under Eugene Ormandy. I think that orchestras in particular tend to sound somewhat the same. But that's up to the conductor, who must have an imaginative set of musical colors within to create something unique. The orchestras are all so good now, they can all play very, very well. I don't know.
New personalities are always interesting.
When someone like Jacqueline du Pre comes along, it's a revelation. Another is Gidon Kremer, who is certainly a personality. Then he must be good. He is good. Vanilla is not good.