I have no idea how to effectively go about adding this feature to the tooling in a way that integrates well with the SysML standard, but I find frequently adding my own temporary legends to diagrams so that I can review them quickly. 

Ideas like "Turn all elements an annoying orange color if they don't have documentation" or "elements with X relationship type are Y color or Z boarder" I find myself adding through structured expressions to legend items. I find that I have to frequently move these legends between models/environments, which gets a bit clunky, and sometimes I accidentally leave these legends on diagrams which causes great confusion for anyone else working on these projects who don't know what these legends mean. In effect, I build a "lens" through which I look at diagrams, though I specifically want not to change the SysML defined graphical representation of these elements in their diagrams long term, just so long as I am looking at it with a certain lens on. 

Is there a more robust way to do this, or is this a feature that could be added? At least for me, this seems like a much more useful implementation of the frustrating "perspectives" feature (which I wish could be uninvented since it causes more trouble than its worth in every case I have ever run into).