> In our experience, it's difficult to create well-mannered commits

Sure, it is. But it's worth it, not just for code review, but for a myriad other things: bisect, blame, log, etc.

Your tool makes one thing (the code review) easier, while decreasing people's motivation to make well-mannered commits, thus making everything else (bisect etc) worse.

I'm sure it's net positive in some cases, and I think it's net negative in other cases.