you shouldn't hack the core and your css rules should not rely on loading orderMy solution has the advantage that I have nearly complete control of CSS via my custom.css file. The only things I might have to deal with (rarely) are inline css.
So, I say to you: give me an alternative that does not rely on specificity or !important rules that also guarantees that my css rules are loaded last. If you can't suggest something that will get me what I need, then I will hack the core until there is a less hacky way to accomplish the same thing.
There is no "should" or "shouldn't" about engineering. It is about problem solving and making choices. There are pros and cons about most engineering solutions. And, this solution has served me very well.