Two matters:
- New Move Types: I think we should start to think about a new movement type: Wheeled Tank. As I am about to upload a new icon for the Soviet BT-5 fast tank, with two switches, the regular tracked tank unit, and the "wheeled" one (maybe with "reconmove" trait?), because this tank could move very fast on its wheels after the crew uninstalled the track from around them, but only on hard surfaces. This new move type should allow the unit to be very fast on dry roads, but to be very slow and clumsy on mud roads and on any type of terrain, except of main roads, cities, ports, may be airfields... Those BT-5 wheels were very hard and narrow, so, the tank moved on wheels, it should have a fairly high ground pressure value. Here, I attach a possible icon for this new movement type...
About switchable infantry: I like the two-switch infantry units, with Heavy Weapons Inf units biased to defensive duties (with its "defensive" switch), and the Light Infantry (or just regular) units biased to attack ("Attack" switch) duties. But I think that -4GD -8AD is a little excessive... It's ok if the unit with such stats usually fire first while making an attack, but you have to bear in mind that the unit will remain in that state, with those stats, during the enemy's turn, and as such I think it would very vulnerable to any type of attack... So, you attack and conquer a new position, only to see that unit wiped out by one air attack and one land units counterattack. Testing should be made to check the values... I think it is Ok to decrease defense values, but the number you propose, in my opinion seem to be a little excessive...
Some more brain-food...
Not sure about "not affected by dunes and rough desert".
