As for the rest of the thread... I don't think Gren spam should be a viable way to play Ostheer. Out of all factions, Ostheer has the best options for combined arms. You've got your snipers, HMGs, mortars, weapon upgrades, anti garrison, vehicle snares, solid AT-infantry etc. All fairly easy accessible with no side-tech upgrades required. If you just make grens equal to riflemen, then Ostheer would just be "all the things allies can do, and more".
This.
And just make the brummbar a bit better vs blobs and Ostheer is fine.