I agree on the right-click to select a clip. That is I agree with you and dislike the change. At least not without the option to switch it back.
I used to have a software app the would allow re-mapping of mouse behaviours in any target program. I used it successfully to change scroll to become zoom (just like Vegas Video, so that my learned behaviour there was consistent with Sonar). I wonder if I could make it remap right-click to left-click when selecting clips? I might not be able to make it work so one specifically within Sonar.
On second thoughts, I'd just like to be able to choose which mouse actions work for me.