Start like this, and you'll soon have different MP expenditures during Assault Movement, or only count par of multiple MP expenditures when an AFV goes from out of LOS to in LOS...
At least, the system makes a difference between AM and NAM movement...
The fire restrictions by MF/MP are obviously a concession to playability. They work fine; anything different would likely imply more complex bookkeeping. What might work OK for a computer game, would not necessarily function on a paper-and-cardboard wargame.
We always can say that everything is fine in the best of worlds.
I am fine with the RAW.
We know that this thread is not about serious suggestions to actually change the rules.
They won't ever change - and it is what guarantees the stability of our prefered wargame.
What this thread could test, is rather our capacity of moving out of a traditionalist and purely defensive posture and of suggesting some "chrome" adaptations - with absolutely no risk to see them implemented.
Officially anyway : some TPP did dare some innovations that would have made people scream if MMP had (e.g. BFP's PiF additional leader values and canister ammo added to some early war vehicles).
That said, the "bookkeeping" would be minor (if not inexistant) if a rule stated that a defender were allowed maximum one shot per 1/4 (no need to round the number) of a vehicle's MP expenditure : we already have to count how many MPs it expends in LOS of the defender to see if case J1 or J2 apply or have to count half the MP expended by a tacked vehicle entering woods or a building.
As much as abstractions are necessary, ASL doesn't present pure abstractions in all domains and one can question the design choices - unless one thinks that Don Greenwood was unfallible.
The system could go further along the path of abstraction and allocate the same armor factors and the same MP to all vehicles : I am sure that most ASL players would state that it "works fine" that way (quite like SL base game didn't have TCA differentiated from VCA).
The fact is that a FT-17 crawling along 5 hexes is less vulnerable to defensive fire than a Chaffee moving 24 - under the sole aspect of successive shots by the same defender.
Now, as the terrain in ASL is quite restricted, that doesn't weigh a lot upon most of the situations encountered (not speaking of the fact that a ROF tear is quite with ROF 1 or 2 Guns)... and a Chaffee still will be able to peep out of a place under cover to rush towards another one, while the FT-17 is so slow that it will get a lot of fire during the next DFPh and PFPh...
And of course there are many factors which will make a difference between firing against a FT-17 and a Chaffee...
But in DTO or Steppe, it has some consequences.