Aye, but that UI element is for weapons only. There’s no easy way of knowing whether your hero ability will reach your allies from a new position until you’re at that position so you have to count squares beforehand. It’s rarely an issue but it’s an annoying limitation/oversight in certain situations and has caught me out a few times when I’ve miscounted.
I’m in agreement with @DaveLong though, when you’re plotting your move you should be able to switch to Tacticam and cycle the range of your abilities from your planned new position (or anywhere you can reach, really) and not just from where you currently are.
For example, I plan to move Rabbid Peach over to my team but I don’t know whether her heal ability will reach them so I plot my movement to a square nearby then hit X to bring up the Tacticam. The pointer snaps to the square Rabbid Peach is going to move to and I can use L and R to cycle her abilities (and weapons) as usual. That’s how I’d like it to be.
For general weapon use though, whether you can hit or not is shown on the UI when you’re choosing which square to move to. That’s pretty elegant, I’ve got to say. I think the only limitation is with explosive secondary weapons which will show a 100% hit chance when your primary might not be able to reach. This can be misleading at times if you don’t pay attention to the little icon next to the percentage.