i think that the term mobile infantry would refer more to bicycles, cavalry, and even some motorized infantry, but when it comes to mechanized infantry you begin talking about vehicles that had some ability to defend the troops from attack, ie armor, defensive/offensive weaponry, or even maneuverability of things like helicopters.
so we could go back to the roots of just what are we talking about to decide on the right name? Would it be better to try and classify two different types of Infantry units, or as upgrades, or based on national facts of what countries had, or an umbrella-unit that covers something beyond ‘Infantry’? Germany had more horses in the Polish campaign than trucks to move materials and troops, so a couple units could be represented if more and more detail is desired…
If it is one new unit that we would be after, I’d still vote in favor of the name ‘mechanized’ because it covers everything up to that while ‘mobile’ would seem to not cover things like half-tracks.
a degree of mobility of 0 i think technically would be no mobility… if one asks how much money you have and you say 0, you do not have a degree of money, you have no money, but that’s just my opinion, i could be wrong… :-o