The major goal of Common Lisp was commonality, and that means incorporating forms from various dialects into one and to maintain compatibility, like you said. That goal has been accomplished.

I think that carefully designed dialects with emphasis on right principles and attention to details leading by people like David Moon would be aesthetically better than a good kitchen sink. It is no coincidence that Common Lisp took most of stuff from Zetalisp, according to CLtL2.

I think it is a general heuristic that a small group of disciplined devoties would produce better artifact than an vast assembly of... general public or passionate and productive but ignorant individual. Think of Python3 vs Ruby, Go vs early C++ or Scheme vs CL. Attention to details and perfectionism works - look at Haskell syntax and prelude. (All this just to illustrate validity of my heuristic).