Why they don't just install these as a removeable app is beyond me. For that matter, I keep saying go out and hire some of the great rom developers to do it right. I recognize the need/desire to differentiate with the custom UI's, but when your custom skin prevents upgrading the latest Android that is a serious issue and customer service failing.
Even from a pure selling standpoint, why they arbitrarily limit their potential market by making the custom UI unremoveable without root is mind-boggling. I doubt anyone would care if it was pre-installed by default, so long as it was easy to remove.
And clearly the wave of the future (or at least where things should be heading) is a Firefox-type launcher where you can install additional features as add-ons. You want to customize the notification bar? Boom, here's an apk to d/l and install otherwise no need to clutter up your OS if you don't want the feature.
It's obviously a completely foreign concept to the OEM's to develop leading software/apps that, if they choose, they could make exclusive to their phones. Looking at what Moto did with the RAZR and "smart" features, they should go buy Tasker or Locale, soup it up and offer as an exclusive on Moto phones. Put some resources behind it to make more user-friendly and you actually have a feature that becomes a REAL selling point (Blur seems only to serve to turn-off potential customers).