Overall grade: D+
Another case of a badly overcentralized kit damaging any potential design space for more UCs. Austria's marriage mechanic is just too powerful on its own; any new components have nothing to do except get out of its way. Augmenting it further would just make an already OP civ even more unbalanced, so the only thing to do is give some tangential bonuses that would be useful for some other victory path that you're never going to take, because Austria is just way too overoptimized for the Cultural/Diplomatic victory path.
Austria - Grenzer
Theme - B. Knowing relatively little about Austria, but given it is one of the least militaristic civs in the game currently, this allowed for a fairly blank slate upon which to choose a new UC. The Grenzer appeared, to my eyes, to be the most relevant and interesting unique unit choice available for Austria, showcasing the constant border conflicts against the encroaching Ottomans and how that shaped Austrian military organization and institutions for centuries later.
Mechanics - F. Overall I would say I am unhappy with how this unit turned out. I think the concept is interesting, but scaling flat CS is not a great bonus that is both hard to tune and hard to convey. I'm left at a loss as to what would make the Grenzer reflect its unique place in history while also feeling like a fun and unique addition to Austria's existing kit.
Uniqueness - C. It scales its base CS off the marriage mechanic, which is unique enough, but I don't know if it really feels like a Grenzer. Fusilier UUs are fairly easy to come up with, and it feels a bit like this unit is squatting on a coveted unit slot that a more interesting UU could occupy right now. It also is stacked closely with the unique Hussar, giving an oddly large power spike for a non-military civ.
Austria - Standschutzen
Theme - D. Knowing relatively little about Austrian history myself, I'm not sure if what we came up with here is particularly emblematic of Autstria. It served more for the realities of the mod, and the choice was dominated more by what we needed to avoid than what we wanted to portray. Still, the UB portrays something of Tyrolean, Alpine Austrian history and culture which is neat, since the UA and UB are very focused on Vienna, and the two UUs are from the Eastern march.
Mechanics - D. It's a CS ally scaler and some military unit production. None of this really helps Austria with their victory pursuit, but Austria is so overpowered it didn't feel right to give them anything that is actually helpful.
Uniqueness - B. It is an arsenal replacement, which is totally unique and far removed from the Austria's other renaissance components.