<p>Looking at MVC framework, it seems we require more of classic ASP knowledge then ASP.NET postbacks and Viewstates. Are we moving backwards to complex UI + code logic in the actual frontend HTML markup?</p>

This is funny that you mention this ... I was having the same conversation with a co-worker today.
Is it a step moving backwards?  I don't think so ... while in classic asp you had a some complex logic in the UI, from what I can see with MVC, the complex logic should still be in your business objects, and any complex interaction with the object should be done via the Controller.
The goal, again, from what I can see, is to keep the UI trim and fit when it comes to actual business logic.  Any additional bloat would be caused by making the UI more user friendly, with the likes of AJAX and JQuery.
This is just my initial observation regarding MVC.  It is a very cool technology, especially with how it sits on top of REST, makes it very easy to work with from other technologies.
I'm looking forward to trying it out in a couple of future projects!