[interface] Select with left click. Act with right click.

[Celtic_Minstrel]

-- You can click and drag a unit to a destination to move it. One click and a mouse movement is all that is required to move a unit.
-- In this single click and drag you can cause your unit to move for several turns if the unit cannot reach a destination in one move, or you can bring up a combat screen.

A click and drag system is an interesting idea, but I don't think it would be as good as you think. What do you do when you want to drag a unit offscreen? On average, a two-click system will be faster then; sure, you can have the screen scroll when you drag the unit offscreen, and bring it back onscreen when the target location comes into sight, but with a two click system you can click once to select a unit, click once (on the minimap) to reposition the view, and then click to move the unit.

[GunChleoc]

I would also like to vote against click and drag. For me personally, it involves a lot of juggling and is a physical strain on the hand.

[fabi]

Click and drag already works since ages.
Exactly like Coffee described it.

He did not want to propose the feature but hint out that it is already in place.

[GunChleoc]

Oh, I see. Duh! It's optional though, so fine by me

[fabi]

Current trunk now features selecting an empty hex field,
resulting in the enlightenment of all units which are able to reach it in one turn.

However, resembling the behavior of unit to field movement, you can adjust the amount of highlighted units
with the number keys, thus highlighting all units able to reach the field in a certain amount of turns,
corresponding to the number key you pressed.
(Wow, what a sentence. I think I do not understand it myself anymore )

Movement into the selected hex field is also possible,
with a simple left click on the unit in question.

This is not much related to the OP anymore,
with the exception that the new feature is much more usable when combined with Metalking's proposal.