It seems like that for the last several years I've stumbled over new stuff that didn't make it to the "What's New" documents (see and ​).  It looks like I found one this year too.  When working in a weldment Part and using the Structural Member function, pre-selecting the sketch line or lines from the graphics area before activating the command works.  It never (as far as I know) did before.  I realize this saves one click at most, and for sketches with more than one line segment it won't save any, but I still kind of like it.  I'd love to have it also work when selecting the sketch from the tree, but maybe next year?