Armylifer, not all of us would agree or at least feel appreciative to have the equipment on our tractors referred to as crap. Since it would appear that you don't have that kind of tractor, maybe you could leave that sentiment to people that have first hand experience.
Many of us are doing fine with these new tractors. So far most people who have had problems have been treated decently by Kubota. I hope that continues to be true.
Second, you are not entirely correct about running the tractor WOT all the time. The dpf filter is designed to accumulate particles, and those particles get burned off either with heavy use or during the regeneration cycle. You can keep the regeneration frequency down with higher exhaust temps, associated with work load. Unlike older tractors, there is no reason to leave them idle, they can be shut off and restarted easily. There was one model in particular that has had trouble getting exhaust temps up high enough to regenerate, but each of these different models in the B, L, and M lines has a different set of emissions control devices, engine designs, and strategies to control particles and toxic gases. You can't generalize from one model to the next willy nilly. I'm not saying there aren't problems, but I am kind of tired of folks condemning them that haven't tried them out. My 2003 diesel truck stinks to high heaven, my tractor doesn't. I am glad not to have particles in my lungs from warming up the tractor in the barn. My .02...