Maybe not top 10 but my life would have been made so much easier by having the facility, especially when recording instruments live and having to sync to tracks received from other sources. It is not possible to play an instrument from the start of a project without a count in, therefore I have no choice but to move the project along from zero, having to amend the in and out times accordingly. Even your fix of an hour along is not without a fair amount of poncing about that could be easily avoided with a mod to the program.
It's horses for courses and depends very much on how people use Sonar, and for what reason. I still maintain it would be a very real benefit to me (and many others it would seem?) and I look forward to the day it is incorporated - however far away that may be!
Anyway, I think I've said enough on the subject now!
Thanks again.
Bob