If you want to give heal to HQ, then it shouldn't be medics. At best it should be timed ability, with 40-50 second cooldown, awaible at HQ after mech is set up.
In this case sturmpios heal will be still usable, because you wont be able to constantly heal all your troops, unless mass retreated and medics would have still have options to exist.
Or even HQ getting medics and Battlegroup getting timed AOE heal.
But in 1v1 the only real true reason why ppl go for med is to get heals. There is no reason to go battlegroup in tearms of the units it gives to you. Better to go for mech and have possible arty\AI LV\AT LV to cover OKW problems.
In teamgames its a different story but it wouldnt change much.
But mech is just too easy to play in comparison with puma and luchs, countering all of the early game of allies until they get ATGs.
Its not like OKW has upper hand in early game against USF\UKF and its not like OKW would have upper hand against T70 and USF LVs. Mech it countering it, but without it you are playing survival mode.
Flak HT is very good and very strong, but about 97% of OKW players are in utter denial about the unit because it has micro tax justifying its IWIN performance even against AT infantry behind cover(as it'll just blast green cover walls and sandbags and pin whatever is behind it quite damn fast).
Except it can be rendered useless and force your STpios constantly repairing it instead of supporting Volks\Laying mines\Sweeping because both USF\UKF can have counters by the time it arrives and Sov can have AT guns by any time if they went T2. Its just too risky to go for AA HT.