I think making the turrets sufficiently different will encourage turret diversity and I believe that is a wonderful thing.
I almost kinda hoped that they'd hook up repair costs to what turret you have, as some turrets were better but much more expensive to maintain due to the new tech within it.
The armor differences between turrets MT-1 and MT-2 isn't really that much. The thickness is identical - turret MT-1 is just larger because the front and rear is sloped compared to the totally flat MT-2.
Honestly, the way they have both turrets modeled and statted in game, with the exception of the weight issue, is done perfectly accurately. I just don't think the structurally-inferior MT-2 turret should give you extra HP to encourage people to use it. Make the two turrets equal in the Hit Point department and let people decide if they want superior turn speed and visibility over better-sloped armor. Turret diversity!
Also, the ARL 44 is a real mess too. The fact that WG decided to put the building-shaped turret from the 1940 FCM F1 on there is a real headscratcher...