Are you suggesting that a dev acting like this without consulting the team should be considered normal/expected? Not sure how to address a move which is unproductive in its nature "in a productive manner" unless being proactive and preventing those rewrites to happen, unless needed and discussed with the team. But in my personal experience the team's decisions were always ignored by the coder in question.

edit: I should remind for context, I have no problem with the rewrite, but I have one with the team being handed over-abstracted code; I found that this happens mostly with more junior profiles, the same that don't stay around for long.

Since this is a fairly common dev experience (rewriting code), that the team meet together to set a policy as a group. Similar to code format standards, why not talk about code maintenance standards?

I get you now, and this is definitely an approach I agree with. I guess I was ranting about my previous experiences... since the last departure I encourage the rest of the team to plan and discuss such changes.