Elite Armor, Luftwaffe GF, and Spec Ops are all pretty underwhelming due to not really offering much the OKW player doesn't already have. Scavenge, Fort, and Jadg give the player more options at least and can fill holes OKW has it it's unit list.
For instance the StG 44 IF has lower DPS than the MG34 LMG, Fallsch are very squishy and very expensive, and the command panther is just to expensive when you might as well get a KT.
Spec ops is the commander I use most of the time.
The Stg 44 upgrade allows you to counter shocks and greatly increased the potential of wiping squads.
The command Panther is better much at destroying tanks than the KT since it has mark vehicle and is fast enough to chase enemy tanks to finish them off. Recon flares are much harder to notice for your enemy than a recon plane and thus work very well with a Stuka. Infiltration nades allow you to clear buildings, which is what okw usually can't really do and it punishes blobber, likewise wipes Riflemen that use hit the ground.
Luftwaffe doctrine allows you to rely on falls in situations where you can't get obers like when you have to go first T2 flak track then t1 for healing and a jagdpanzer. Volks and sturmpios just don't work after 15 minutes if you face allied elite infantry.
Additionally they kill snipers when popped our correctly.
Valiant assault allows you to chase tanks with your volks or kiting snipers. Luftwaffe assault gives you a free squad when you are low on manpower and the strafing stukas pin and kill enemy infantry, very useful in late game vp struggle games.