I am 5'8"-5'9" and don't mind the seat height. At first, I also thought it was a little on the tall side but now it seems more natural. Tall seat helps the visibility for the 3 pt on my 5610. When I get on my JD 4520, I pump up the air seat to make it higher and like the taller seat height. I think the high seat is due to the larger capacity of the fuel tank.
The clearance on the D is 9" with the larger tires. Not the greatest. My prior JD 3720 had about a 10" clearance at the drawbar/transmission. I also have a skid steer and the clearance on that is also marginal. I have learned not to go in deeper snow with the TC or skid steer. It will cause too much drag and I have been high centered. I have learned to dig, plow or blow my way through snow and keep any residual snow under the height of the spine frame of the TC. Part of the problem is the tread design which IMO, is poor for traction on the TC. It needs an R1 lug design option. What was the clearance on the older TC series? The older design didn't seem to have much clearance either.
I don't think the noise in the cab is any greater than my prior cabbed JD 3720 or my current JD 4520. I also have large ag tractors with cabs. The noise is very acceptable in all. There is considerable sound insulation between the motor and cab. If you want bad cab noise, drive a Kubota 1100 RTV. The noise is terrible and unbearable IMHO.
Stability with forks is a non issue for me. Vastly more stable than a CUT with a pivoting front axle. I modified my lift arm cylinder and can lift nearly 3000 lbs but rarely do. Don't worry it is stable. It may seem a little unstable due to the give in the rubber stops on the suspension. You have to love the smoother suspension of the D series.
