Three disclaimers before I start:
I haven't read every post, so some may have mentioned these already.
I'm still on SU 2015, so the newer versions may have these features.
I'm not a SketchUp Sage or anything like that, so I may even be overlooking these in my version.
Now for my requests.
1) (SketchUp) Inference from guides. For example, when performing a move-tool command, I can only line an entity up with a guide if I find an intersection, but when I line the entity up with a line, I can pick a point anywhere on the line.
2) (LayOut) You know how we can create inference in SU by hovering over a point, then moving in whatever direction to show that dotted line? I want to be able to dimension like that in Layout. Imagine a kitchen elevation, and the boss insists that all dimension lines begin outside the wall. If I begin the dimension command somewhere in the middle of the drawing, then drag to the outside, I have to manually re-size every one of the indicator lines. If I could infer from a point, I would only start the dimension command once outside the wall. (Try to include screenshots later to show what I mean.)
3) (SketchUp) Program performs dimension calculations. I begin a line, then instead of typing 24" Enter, I type 12+12 Enter, and the line is 24 inches long. I've seen this is in Thermwood's eCabinets software, and it's really helpful when you're doing a rush job, and dealing with 5-7/16 minus 3-3/8 or something complex like that.