For the sake of comparison, the SdKfz 234 is roughly the same size as an LAV-25. Weight for both as roughly 12 to 13 tons, depending on variant. Ultimately, the drawbacks of the Puma compared to more modern vehicles are the engine and the suspension. The Tatra 103 is a four-stroke diesel with greater displacement than the GM 6046 in the M4A2, but providing only about 200 horsepower. In terms of power per displacement, it is similar to the Kharkov V2. Before turbodiesels became common, four-stroke diesels are not a particularly good idea for armored vehicles purely because of their size. The issue with the suspension is the amount of volume that it takes up inboard of the wheels. The system uses four sets of leaf springs, each of which connects two wheels and is able to use upward force on one wheel to push down the other wheel, similar to a spring bogie system. The result is that the Puma has relatively little protected volume for its size.
As we know, armament options are a 20 mm auto cannon in an open turret, a 75 mm short gun in an open casemate, 75 mm anti-tank gun in an open casemate, or a 50 mm anti-tank gun in an enclosed turret. I'm like modern vehicles like the LAV-25, no Puma variants are capable of carrying dismounts. If you're looking for a better armament option in the post-war., My suggestion would be a 3-inch smoothbore low pressure cannon like the PAW 600 in a fully enclosed turret. HEAT warheads by the 1950s should be enough to defeat armor on almost any medium tank you encounter. I would not recommend keeping vehicles like these around beyond the 1960s.