LemonJuice have some good points imo.
Not alot of players goes priest or B4 to hard counter the pak43 at 8 CP. But even if they did, those two doctrines have no hard counter to the KT which is what OKW should be saving for anyway. With good truck positioning pak43 is much easier to defend than OH pak43.
Pak43 also allow OKW to go abit more heavy on obers and mines. Once the KT is it out OKW can then convert fuel into munitions to get more shreaks, mines or zero artillery to prevent medium tank flanking the KT.
As for OKW mobile AT guns, LEIG hollow charge ability is more reliable long range AT than the raketenwerfer. LEIG hollow charge has more armor penetration and 2x range vs raketenwerfer. So why even bother with the raketenwerfer?

LEIG fit pretty well with the WW2 idea of one all purpose AT/AI infantry support unit. Work best against USF when they are repairing tanks with tank crews or slow soviet tanks.