I've done massive refactorings in the past as the parent is suggesting. But before I do it, I try to figure out whether the code is hard to read because the dev

I've done massive refactorings in the past as the parent is suggesting. But before I do it, I try to figure out whether the code is hard to read because the developer was bad, or because a good developer was forced to add support for hundreds of edge cases over the years. If I notice at a cursory glance that I can replace more than a few ridiculously convoluted chunks of code with something simpler and be sure that I broke no edge case for those chunks, I just assume that the previous developer was simply incompetent and rewrite the whole thing to meet the original requirements. (And perhaps down the line a developer better than I will do the same with my code!)