Ruff, I think I know what you mean about PLE's unit selection code. I installed PLE by itself to play around with the full thing. I like the view options, but the selection code is frustrating.
The main problem is that if you add units to the selection (shift-click), it automatically creates a group out of the new selection Inversely, if you select a group, then select a single unit in that group, and finally issue an order, the whole group gets the order -- not just the selected unit.
Perhaps after using it for a while I'd get used to the way it works and find it just as easy as the normal method, but I doubt it. The normal method was intuitive to me from the start, whereas I find PLE doing things I just don't expect. Is that why you stripped out some of the PLE code for your mod?
I'm going to look over the code more thoroughly, comparing it to the normal game, and see if I can fix it.
I'm afraid that because I'm not much of a warmonger and don't build stacks over 20 units in general (30 max), I may not be the best judge of PLE.