Like many other people, I sometimes have trouble clicking exactly where I need to in order to interact with a partially-obstructed target.
So, I suggest some hotkey modifiers that change how the selection cursor works.
First: Either the default cursor behavior, or perhaps holding ctrl should change the normal cursor to a 'box' cursor like the original xcom one that disregards obstructions and highlights the selectable square. It was a really good idea that works really well in an isometric environment. Perhaps an interface option to set which is default and use ctrl to switch between them?
Second: Holding alt or another hotkey should change the targeting selection to aim at the center of ground-level for the selected tile. KABLOOEY!
I'm sure we can think of some more possibly useful selection modes. Anyone else have any ideas?