Electric locker!
90% of the times I have needed it, I have needed 3 feet to engage it. Usually I am in an "oh crap" situation on a steep bank or coming out of a hole and need my left foot on the brake. Taking foot off break = death. OK, so put right foot on locker... uh, now how do I actually move? Stupid design. Worthless in fact, unless you are good at Twister.
I'd accept a hand operated mechanical locker, I suppose.
Another problem with the locker is it requires quite a bit of wheel rotation to engage. If I need a locker, I kinda need it right now. Not 3 inches deeper in the mud from now.
Less hardware and wiring underneath. I've had my electric diverter valve come unplugged twice. That took a while to figure out the first time.
Another vote for improved mixing on the loader SCVs. It can lift and curl at the same time, but it takes quite a bit of concentration and can be sloooow.
+1 for toolbox or at least a spot for a toolbox
Perhaps an unrealistic request, but I'd like to see throttle detents or an adjustable mechanical limiter. The lever is stiff enough that slow force is about as slow and accurate as just striking it with the palm of my hand. I'd like to get to PTO speed with a brain dead shove, knowing it will stop at a point I have set. Perhaps my throttle is just a stiff sucker?
A radiator support that isn't directly in the way of the air filter cover. Dumb!
A PTO cover that will stay up on it's own. Perhaps mine is not normal?
A top-n-tilt that will tilt BOTH ways. As an experiment I put the turnbuckle that was replaced by the cylinder on the left side and lengthened it way out until I had equal tilt both ways. Problem? Not enough tilt, and now the 3PH doesn't go nearly as high. Shame.
An improved diverter valve switch. With gloves on it can be a pain. A momentary push button on the top of the joystick would be major cool. I have little need for it to stay in diverted mode. Usually I click, adjust, click. Perfect for a monetary pushbutton. And if the monetary pushbutton doesn't work for you, put the dang indicator light on the dash.
Crusie control buttons on the steering while, like true automotive crusie control, eh? Having all those buttons way down on the right side is just dumb. Why take my hands off what they are doing? Why do I need to look down?
Another crazy request: dash mounted 3PH tilt indicator. Man that would rule!
Seems like a long list, but I am happy with my 3520. I'd buy it again for sure!