Seriously though, I don't think there's "healthy conflict". There are healthy relationships where you can someone they're full of it without it being an insult or you can discuss how to write better software without it being perceived as a personal insult. An environment where people want to grow, are curious, are friendly, and just talk about how to do things better. Once you're in "conflict" territory it's something else. Unfortunately in most organizations you actually do have to get into conflict territory to impact change but I don't see that as a positive thing, just a negative that is a fact of life.
EDIT: This "I noticed blah" pattern is what's taught in formal management training as a method of giving feedback. I know because I've done those. The problem is that wrapping negative feedback in some formulaic pattern is transparent and doesn't work. So the person receiving this immediately strips away your formula and hears the negative feedback. I know that's what I do when someone uses those tools on me. The way forward is not to use those tools but to engage in a true positive way and foster a positive atmosphere. A smart person already knows there's a problem when their code got rolled back. The discussion shouldn't be about their performance "issue" but just about assigning people jobs they can handle and giving them tools and support to that right. There are exceptions when there are more complicated things going on, but the way this is handled when people have good intentions and are motivated is to generally keep helping them stay motivated and have good intentions even when they make mistakes.