Can we have some more tank-destroyers? Personally, I would suggest:
the "SP 17pdr, Valentine, Mk I" aka, the Archer. Yeah, its slow, at only 20mph. Yeah, its gun is facing the rear of the tank. Yeah, it only had 60mm of armor. But it had a 17lber, a low profile, and was a good ambush weapon. Reverse into possiton, fire a few rounds, and then just drive off without having to turn around.
The Sturmgeschütz III (abreviated as StuG) Ausf. F (with StuK 40 L/43) and the StuG III Ausf. G (with StuK 40 L/48. Low-profiled and well protected, these would make great ambush weapons. Wouldn't have quite the same punch as the Archer, but the better speed, protection, and forward-facing gun would make up for it.
SU-100 With 75mm of sloped armor, a relativly low profile, and the powerful D-10S 100mm cannon, the SU-100 would be a great addition. It would be fast at 30mph, with a low profile, good armor, and what would probably be the second best gun in the game, bested only by the 8,8cm KwK 43 L'71.
Jagdpanzer IV Both the SdKfz 162 version (armed with the StuK 40 L/48) and the SdKfz 162/1 version (armed with the StuK 42 L/70). Better armored than the StuG, having a bit better sloping, and with more ammunition capacity, but being slower, and a bit larger overall. It would still have the armor and low profile of the StuG combined with the firepower of the Archer.