I've read the different opinions about the steering with interest.
I haven't driven enough Kubotas to know how other models steer, but our 60hp
M59 with HST+ and a similar engine to yours is probably similar to other Kubotas that size.
I don't see any way that the steering could be better. Even with a ton or more in the bucket, on hard surfaces moving the steering wheel moves the front tires very precisely and all done without any effort. It doesn't matter if the tractor is moving or not. That is probably as much due to our hard sandy non-compressible soil and the flat-profile industrial tires as to the power steering. I could see it being much harder to turn if it had lugged R1 ag style tires with the loader bucket full and the front tires sunk in soft soil,
If you question the steering, maybe trying some of the other tractors on the dealers lot may set your mind at ease. On a hard packed surface, I'd expect the steering to be effortless regardless of the load in the bucket. But it will be very different in soft soil. In real soft muddy soils I wouldn't expect the steering to work at all unless done carefully while moving. Trying to force it will just break something.
These 60 hp Kubotas are medium size, medium duty tractors, so they do have limits. You can overload them and hurt them if you try. There is a huge difference in strength and capability between our 60 hp Kubota TBL and the 90 hp John Deer 310 - which is basically the industrial version of the same kind of machine. On the JD, even a novice operator would be hard pressed to make the machine hurt itself.
rScotty