Earlier quoted context omitted.
I do. Having worked with so many engineers with almost no social skills, I think there's a lot of room for improvement in their communication style. "Why didn't you do it this way?" is aggressive and critical. "have you thought about this approach?" makes them feel like you have their back and are trying to help. I agree there's not a huge need to the "I really liked how you tackled this" part but even never praising…
It depends on context, but I have found the opposite. "Have you thought about this approach" can come across as condcending. Of course I thought about that, it was the first thing I tried before the much more complicated solution that actually works. "Why didn't you do it this way" invites them to share the war story of what happened when they tried doing that.
That said, I never liked the 'sandwhich' method, saying; "Great effort. The result is horrible, like your indentation though."