A modification to how Fallschirmjager work fundamentally could be a good way to revitalize the doctrine.
They currently are pseudo elite infantry that overlaps heavily with Obersoldaten and thus are rarely better than the non-doctrinal Obersoldaten.
I suggest reworking Falls to be more like super-Volks. They would do everything Volks do, but better and at a slightly higher cost and have different veterancy bonuses that include their camouflage.
New Fallschirmjager: 5 man squad for around 300 manpower with 5 Grenadier K98s and an upgrade to gain 2 FG-42s for 60 or so munitions. Abilities are panzerfaust and a regular grenade plus the frangible smoke grenade but now the frangible grenade is unlocked at Vet 1 with passive cloak unlocking at Vet 3. They would also be available to drop in at CP 2.
The concept here is that while intended to be elite assault troops, Fallschirmjager actually ended up being used mostly as regular infantry units and some even being formed into armored units as crazy as a FallschirmPanzer unit might sound. This implementation gives the OKW player a really strong reason to go for Luftwaffe Groud Forces Doctrine, better core infantry. Once unlocked at CP 2, there would no longer be any reason to get Volksgrenadiers, except for the lower manpower cost to field them or the lower reinforce cost. Falls now can become your core infantry, supplemented by Volks you may already have, but give you better fighting strength at the cost of a little extra manpower. The true cost of of the doctrine is that it isn’t special operations and so it has no command Panther or any other call in units. Essentially going for Falls now has no major downside early on, but becomes more expensive to upkeep and reinforce late game and with no special late game unit in the doctrine.
Pfusies already exist, and when they were 2cp people complained that they were unusable and too awkward to fit into a build. I think falls should just be a bit tougher, like stormtrooper RA and they'd be fine. They've got great DPS at all ranges, 2 excellent grenades, camo, and a faust, and they come at 3cp like other elites.
Relic Entertainment
Heartless Jäger 
