Yes I played the mod. Yes I used the new Ostwind. I like the new Ostwind, I like the new USF and I love the call in changes! But my concerns are not with the Synergy of Ostheer. Rather the fact that tier 4 still ins't viable because you can't go ahead without getting a deep tier 3 build vs USF. This means you will most likeley never get to tier 4 since you need tier 3 to crutch yourself through the game.
This is not a fault of your balance design. This is a faction design flaw that you guys have to work with. The new TWP is really nice and its mg performance is indeed better. But a Jackson can kite it forever and be protected by usf infantry with bazookas and bars, to which the stug is very vulnerable (rightfully so).
A Jackson in its balance preview state played right, is something that can basically shut Ostheer down when supported by a USF heavy infantry play.
This is my big concern with the Jackson health buff as well. Ostheer crutches on its t3 units more than any other faction due to its defensive playstyle vs USF and the Jackson utterly shuts it down with its high mobility, range, dmg, and now health combined with excellent spotting riflemen.
Its high mobility is what sets it apart from all other TDs. That's why it has the poor health as a trade off to give it a proper counter. You don't lose jacksons against ostheer because they're weak. You lose them because you make a huge mistake.