Ah! Now we come to musings on game interfaces and design.
It seems to me, (although I am not a professional interface programmer), that interfaces in games went through 2 phases. The first phase was heavily button based, normally the screen was segmented into view areas and control (button) areas. In this era I am thinking of games like the original Command & Conquer, X-Com, Diablo I and II, Starcraft I, etc.. While there was interface aspects in the main view (selected unit icons, damage bars, etc..) the main focus for the interface was away from the view area.
As time progressed and it became easier to do transparency and glowing images over the main view we start to see more highlighting in the main view, such as movement areas, shields, etc.. (Starcraft II and Civilization V does this to some extent) and a reduction in the number of buttons present on the screen. This is also because as complexity increases it leads to more and more buttons which can reduce the view area visible anyway.
The advantages of shifting to an interface overlaid over the main view is that it can help reduce both the amount of button controls needed as well as provide more information to the player at a glance (showing movement areas). Having indicators overlaid over the main view also keeps the player from splitting attention between two different parts of the screen.
The disadvantage is that the main view becomes more cluttered and can be obscured - it also trades complexity in the button view for complexity in the main view. It's a balancing act and can make things even less approachable to the new player than having clear buttons.
Nevertheless I am a firm believer in the more dynamic interface overlays in the main view approach. I tried to do this in Chaos Groove and minimise the buttons and it really helped (IMHO).
I will do the same if for this game, although it will be harder because there is more complexity in the movement and attacking that in Chaos (directions to face, line of sight, different types of firing). Still I think you will find that I push the interface towards this direction much more than I've seen in any other turn based game (although I haven't been keeping upto date with them recently, admittedly).
I'll talk more about this in the future..