The Lisp-1 vs Lisp-2 issue is really a matter of personal preference. Going to Lisp-1 gains you nicer higher-order function syntax, but costs you twice as many namespace collisions. It depends what you want.
Scheme define vs CL defun is a total non-issue. I'm glad he discovered that.
I program in Scheme all the time and rarely use call/cc.
I've used both types of Lisp extensively, and I'm now convinced Lisp2 is a mistake. There's not really any downside to not making that mistake. I program daily in a Lisp1 (Arc) and I don't get any more name collisions than I did using CL.
Proper seperation of functions into modules makes the namespace collision issue a non-issue. Now, you might consider the fact that the Scheme community is divided and the lack of a standard module system an issue.
Scheme define vs CL defun is a total non-issue. I'm glad he discovered that.
I program in Scheme all the time and rarely use call/cc.