Ostwind is totally fine for its costs imo.
Well you need 2 of them with Suppression bulleting (to the mg on it) to fight blobs. Even then you need to kite trough whole map and wish that neither of those ostwinds don't get stuck. Yeah even partisans can run like idiots towards them and shrek them to pieces.
It's decent when you suppress something with MG42 and push ostwind to kill it but mortar will do the same better and cheaper.
Only reason i build them nowadays is that for some reason strafing airplanes seems to hit the ground when i have 1 of these on the field.
Just add suppression to it or damage multiplier when hitting multiple enemies at the same time to discourage blobbing.