I don't know about "many" design flaws, but the brake itself is pretty useless. I put mine on a nice little incline when I wash it down and have had it roll back on me when I take it out of neutral before. Very disconcerting.
At a fair the other day, I sat on the smallest tractor (tractor, not mower) John Deere makes and the controls were oddly placed, difficult to actuate, and otherwise non-intuitive. Farmer Bob could probably hop on it and be happy as a clam, but for us suburb folk, Kubota makes a very easy to manage machine. Point is, they're pretty far out of the box on some of the things they put on their tractors and they aren't always perfect the first time out. Or the second. Sometimes the third...
But I put the brake in the same category as the droopy door hinge on my old Ford Explorer...after so many years, don't you think they could get this basic thing right?