Common Lisp had different goals from Dylan. Common Lisp was designed as a powerful Lisp dialect, incorporating ideas from 20+ years back plus some new stuff. It was designed to be 'backwarts' compatible with Maclisp and its dialects.
Dylan was designed as a new language (compatible with nothing) for application development and delivery for small machines.
And many of the people involved with that were also involved with the Common Lisp standardization (like David Moon, Scott Fahlman, etc).
Common Lisp is a pretty interesting example, but due to the politics of the various companies involved, the vast amounts of code in each of the various Lisps, and so on, I don't think it is a fair reflection on "designed by committee". It is just what that committee was able to design given the constraints imposed upon them.
In many ways, Dylan was a stripped down and much more minimal Common Lisp, but with aspects of Scheme as well. But Dylan was designed from a green field, while Common Lisp was designed with a number of existing Lisps in mind that each had a stake.