Based on the German Minor Set 1 tank destroyers stats are A-D-M-C 5-5-2-5 with target selection: 1-2 (armor class units). Does this seem a bit OP given medium tanks are A-D-M-C 6-5-2-6 w/ blitz ability.
Btw how many of you use the tank destroyer unit for all nations in your games?
This target selection is based on an over-amplified bias toward tactical combat scale.
At strategic level, a given division has to fight other units which are in a given TTy and cannot pick according to its taste.
And compared to a Tank, a 5 IPCs targeting unit with one small offense pip (on a 12-sides dice) less is clearly better.
Fortunately, blitz is for Tank.
You may think about lowering some combat values but add a combined factor with Tank, Mech Inf or even Self-Propelled Artillery.