I've had a few bags repaired or replaced and the outcome is always better when it's replaced, in my experience. But then, the damage my bags have suffered are things like a snapped-off handle (one of the telescoping ones), or a missing wheel.
For minor damage as you're describing, it sounds normal. If you're handy with things, you might well do a better job repairing it yourself. If you leave it to be repaired by a service, it is unlikely, again in my experience, to look anything close to new.