Having gone through a few ASP.NET MVC tutorials I would tend to disagree and say I dislike MVC as I would be writing hundreds of lines of code in various places to do what I would do in a few lines in a powerbuilder application. That being said I can see where you are coming from with the need for a datastore to be held in a web service to match the html client data for updates/inserts.
I think the webserver (asp.net/jsp) should be cut out all together and they should be focussing on single page application style architecture with the datawindow layout being held as html and data loaded/updated from the web service. My biggest problem with my current web datawindow sites is that I cannot update more than one datawindow on a page at a time due to the need for a page refresh.
For my way of thinking business applications are still even on the web going to be made up of hundreds of datawinows spread across lots of pages and datawindow reports being run on this data. At the moment I cannot see a web tool out there that quickly allows you to define the data and layout on the pages (like a datawindow). Some out there like Kendo have great grid components with resizable, draggable, sortable, filterable columns but are not graphical defined like a datawindow and don't go into the free form style. I think there would be a market out there if they can get something together with a html5 datawindow with other modern components definable on the page like panel bars,tab strips, menus, multiselect etc.
Obviously this would need to be a separate target and wouldn't care if I had to do the client coding of events in Javascript/Jquery or a powerscript blend.