Well, when I was picturing it in my head, the major problem that small size on a vehicle of that weight (the Black Knight is 12 tons, this vehicle just
slightly more than double that) is ground pressure, allowing a turret that can accept the elevation capability (given that newer IFVs are having AA-grade gun elevation like the Griffin 3... and they're in the same ball park as the M2) to target higher skyscraper targets (which means 85 degrees), have a respectable ammo load for the autocannon, and fitting the entire AI assembly
and the powerplant that is capable of powering that
and everything else is going add up. This has to go across multiple types of terrain mind you.
Also, don't believe me that newer IFVs are getting AA-grade gun elevations, the Griffin 3 would like to have a word with you (and this is a close development with the US Army mind you):