There's a few issues with the sequence, though most of them involve just getting practised with the system.
However....
Hull and Armour:
The better materials are too heavy to be worth it. Less so with hull, but the bonded armours are heavier per armour-point than crystaliron. Space-wise for armour is negligible, so this means TL12+ armour is disadvantageous.
Solution: reduce weight for the bonded armours; in terms of the vehicles in the books, this will reduce their masses, and therefore increase the listed speeds.
Also, sloping and supersloping are a waste of effort, with a vehicle both slower and less armoured than if it hadn't bothered.
Eg: a 100m3 MBT, with supersloping, has only 80m3 to play with, but still weighs as much as a 100m3 model, for a gain of 20% of armour, which may only be worth 6 or 8 points.
The 100m3, w/o sloping, can use that 20m3 to add the armour it would gain from sloping, which, of course, adds mass, but little volume. The 19m3 left can all go into powerplant and fuel.
Conversely, an 80m3 tank, w/o sloping, would be superior in both speed and armour to the supersloped 100m3 version.
Sloping may give a slight advantage when it comes to ground pressure, but the extra powerplant more than makes up.
Solution: don't use sloping... 
Powerplant:
Turbines compared to fusion are too powerful. Especially when turbines over 10m3 get a x1.5 efficiency boost, and fusion plants do not. In fact, hydrogen fuel cells also get the x1.5 at 10m3, and have the same fuel efficiency as fusion.
Solution: increase the power rating for fusion, by % increments per TL, rather than by 2 points/TL. This will then increase the speed of the grav vehicles.
I've puzzled over the design sequence for a bit now, and these are only my feeble ponderings based on redesigning the same vehicles several times to get the best out of them. Be interested to note what other folk have noticed.
Ammo needs a little work, too. No way 40 rounds for a 35mm railgun should take up a volume 3 times that of 40 rounds of 120mm anti-tank!
