I think we are just about ready to fully retire the old stemwall tool. The only thing I am missing with the new polyline tool is joist pockets, I guess there is always one more thing.
Joist pockets would be a feature that would be on a per edge basis. Like brick ledges for slab-on-grades there would be no "move" function, only draw, edit and delete tools. So essentially I need one more toolbar for joist pockets, with three icons... I know everyone is about ready to hit me right now, with all of these toolbars I keep adding, I'm sorry.
In my defense though I should point out that the user can easily disable/turn off any of the toolbars that they do not commonly use, so that they do not overly clutter their SketchUp workspace.
Joist pockets are not a high priority in my opinion. I have a few western US builders who use them on a regular basis but I don't think they are as popular anymore. I'm going to put this option on the back burner for a while, however as they say the squeaky wheel gets the grease so I'm always open to suggestion if you feel otherwise.