On the topic of new objects and the like. I think that depends on two things really. First would be if they add support for modding that deep. Mostly because if they add modding, it would potentially give this game years of longevity. The second would be if they want to do DLC or not. I could totally see them making packs of ten-level dungeons that include new loot and skill trees for the price range of 3-5 dollars each (Potentially, these new dungeons could also go into a 'ultimate dungeon' mode, which basically stacks all the dungeons together and starts creating branching paths ala NetHack)
Personally I wouldn't be against spending another 5 dollars if they created a DLC with a similar level of content to the base game (3 dollars if it's just a bunch of new level textures and items though). Assuming of course they are not simply reusing art resources and etc.
Heck, I could see people being willing to pay for new player models and the like as well.
Of course, if they do go the DLC route I sincerely hope they don't make 'every' piece of new content DLC only. That would be painful.
Edit: Oh right mr. macduggan. I had a decent build going on pre-patch that involved Archery/Viking Magic/Promethean Magic/Magic Training/Blood Magic/Burglary/Tinkering. The idea was to keep Viking Magic up for the awesome ranged damage add (Which completely ruins your magic regen, hence the blood magic) while you have some solid magic spells to get you out of sticky situations (I rushed the pet dragon in Promethean Magic, then went for the first point in Archery for the ranged damage bonus)