Ah thanks for that!
Due to geographical differences, we'll be mainly using roll20, so a grid helps when positioning tokens etc.
I like the 15m/MP idea!
As a side note, i dont have the rulebook on hand right now, but in aToW do characters need to declare their facing direction like in BT? Or is it assumed that no one will be unintentionally staring at a wall in the middle of a firefight?
in my copy of ATOW (hard copy) the best answer is a qualified not really on pg165 under movement and turning a character can make up to a 120degree turn for free during their movement (2 hex sides) as an incidental action ie it doesn't count, any additional turning costs 1 mp per 60 degrees to reflect the "tightness" of the turn.
so the answer I would say is that it does take facing into account but walking (equivalent) movement is an incidental (automatic) action that the character doesn't really have to think about.
this also of course takes into account situations where someone is running into cover and face plants a wall, or spins at the last second, and slams their back into the wall because it also talks about "turn modes" which to me... means look at the turn modes charts for things like vehicles, WIGE vehicles, and aerospace fighters where the speed the unit is traveling can affect its turning capability, (if you want to it actually makes a lot of sense to apply the concept to people as well) so a person can walk at say 6m/turn (5s) and turn 120degrees for free 2 movement in, and then another 1-2 movement later can repeat the "free" up to 120degree turn but if they want to turn "tighter" than that (as defined by their speed) they have to pay "extra" mp to accomplish it (the best of both worlds.
for simplicity sake if you are playing on square grids and not hex grids, we always broke it into effectively 8 facings which gets you 45 degree increments so you could simplify the 120 to 135 degrees (IE 3 "virtual) sides as a free turn
the practical aspect is that when using the "virtual" 8 sided spaces in a square grid, the additional "virtual" sides are the diagonals (ie set a second square on top of the first rotated so that the flats "centers" align with the corners of the base grid.
http://www.greenpowerscience.com/OCTAGONCAL.html shows the concept except that you would actually compress the actual octagon into the square for simplicity purposes. of course D&D allows you to move on the diagonals for a 50% movement cost increase, which I don't think you necessarily need to apply.