How would you handle 7 singles units on the same tile?
Now it is click tile, click the required unit Icon, click action.
Having your suggestion be doable could present an issue with units that block each other out, graphically, such you would be force to first rotate the map/screen until able to click that outside unit from the back row of the original viewing angle, but then may still not have click-able access to units situated in the middle of the pack?
They are not mutually exclusive, and in fact, would work well together.
If you have just 2 or 3 units, then selecting the individual by clicking on it would work fine. If you have 7 units, the current method would work best if a player can't click the correct unit.