I've been working a lot with parametric design software (TopSolid, Fusion360, ...) lately and I think a few of their characteristics would be more than useful for architects.
My wish would be to see "construction quotations" and "parametric constraints" added to ArchiCAD.
Let me explain further those two ideas.
Construction quotations :
The idea is to have a new tool that lets you put construction quotations on your plans. These are a different thing than documentation quotations and they would never appear on layouts.
Their only purpose is to let you decide a few dimensions and fix them for good.
For example, if you draw a portion of wall with a window in it and you want it to always stay 50cm from the extremity of the wall you would just draw the construction quotations (attached to the correct items just like you do for traditional quotations) and specify a length and if you then move this point of the wall, the window would always be 50cm from its end.
Constraints are rules determining how two objects interact with each other geometrically speaking (does that mean anything?).
You could put a perpendicularity constraint between two walls and no matter the position you put them on they would automatically stay perpendicular.
Same thing with parallelism. There a lot more options for this tool, I won't list them all here.
The best example of this is found in TopSolid for me. I highly encourage you to take a look at how it works (a simple example : https://www.youtube.com/watch?v=-y8T6R8IXmQ). You also find them in Autodesk Inventor or Fusion360 or other similar softwares.
If you combine those two tools, you can do really good thing and improve your productivity and precision dramatically. If you use it right, it lets you easily test iterations of a design.
A simple example concerns construction grids. If you draw it, build your project on it and later need to modify the grid, it can be a real pain in the a33...
With these tools you simply edit the construction quotation that you need to modify and every wall and everything on the plan moves accordingly to your modification.
If you couple that with the possibility to have a list of variables predefined, you can edit multiple occurrences of one measuring at once.
Well, I could go on for ever with examples but I will stop here.
I would really love to see ArchiCAD implement this. I realize the solver behind that is quiet complex but I really believe it's worth a try.
EDIT : That is exactly what I mean : https://www.youtube.com/watch?v=Vm30vgnso7Y