To be honest I would prefer the numbers to be more realistic to their historical makeup, which would be more equal than they are now but not all the same either. However, stats MUST be changed to reflect those numbers in the division designer. It is nuts that you have to build 60 light tanks to replace 40 medium tanks to achieve the same firepower even if they have the exact same guns equipped. (please don't argue medium tanks are more effective because of their armor/size/crew, that is taken into account with the battalions other stats)
I do believe it is more important that all AFVs take up the same width to make balancing easier.
I like that a unit designation like TD or SPART lowers the numbers needed in a battalion. As long as the stats are balanced by PROPER modifiers, it is all good.
I don't mind that designating the same exact vehicle in different roles in the division changes its effects. Designating a tank to an artillery role in your division increases its SA, decreases HA and breakthrough, and increases supply consumption by quite a bit. Then they cost less because it doesn't take as many vehicles to fulfill that role. That is pretty realistic IMHO. I do think the penalty to breakthrough and HA are too high however. If SPART had a width of 2 I think the extra SA and lower cost would be worth adding to divisions without making them OP.
Another problem with the designer is that there are no options for open topped vehicles at all. They are just mixed in with all other vehicles?
I find that the biggest problem with the designer right now is that the guns are WAY overpriced (especially in resource costs) and the turret is WAY underpriced.
A hint for everyone... I did not notice this mentioned on this thread, but you can put a light fixed superstructure on your medium tanks with the exact same stats. The only downside is you can't equip large guns. So, If you are putting medium guns on your medium chassis, the small fixed structure reduces the cost for the vehicle by .75 production.
However, that is all a moot point. Because currently the simple answer is this. You should never ever ever build anything with a fixed superstructure until the tank designer gets balanced. The 3 man turret is the king on everything unless you never plan on attacking with your AFVs? Who would do that?
The only advantage to the fixed superstructure is 20% reliability and 3 defense. (Why a fixed superstructure gets 3 defense vs a turret, I have no idea?) The fixed superstructure costs either .75 (small) or 1.5 (medium) 5 (large) production. The 3 man turret costs 1, 2, 5.5. So for a little extra production you gain 20 breakthrough with a loss of 20% reliability and 3 defense. However, with the way breakthrough gets multiplied by the radio up to 65% it overwhelms the 20% flat reliability which never gets increased by anything and the measly 3 defense.
My suggestions to fix the problems I have raised...
1) Decrease the cost of the vehicle gun by about 2 production and a tungsten on average. They should enable for fractions of resource to be used, like .5 tungsten to be used in some cases to make the system more flexible and have more gradual cost increases.
2) Decrease the fixed superstructure cost to .5 (S), .75 (M), and 1 (L). Increase the cost of the one man turret to 1 (S), 1.5 (M), the two man turret to 2 (S), 3 (M), 4 (L) and the 3 man turret to 4 (S), 5 (M), 6 (L). A good 2 or 3 man turret cost as much as the gun to produce.
3) Have an option for both fixed superstructure and turrets to be open topped. This should significantly increase their firepower and supply usage, decrease their cost, and give a malus to defense, hardness, and breakthrough.
4) Make all vehicle battalions have the same width and make any necessary adjustments to artillery firepower to keep game balance. Although right now I would think only leg ART and towed ART would need a little nerf.
5) Decrease the cost of the chassis a bit to bring overall cost of AFVs down. They are either overpriced or too ineffective on the battlefield right now to be balanced with softer units like INF and MOT! Or perhaps soft units need a little nerf. Either way works for me.