We wouldn't be seeing all these construction walls, that's for sure!
If DCA opened with more immersive lands to begin with, there obviously would be no need for the slew of projects going on right now. But if it had been done right the first time, who's to say it would have been better than (or as good as) what we'll be getting in 2012?
I guess my point is, sometimes working around a current challenge causes the imagineers to become more creative than they would have been with a clean slate. For instance, the challenge of turning sunshine plaza into Buena Vista Street. Sure, BVS would have been more "ideal" with more space, freedom to place buildings where they chose, and no monorail running through the middle of it. But instead, they had to work with and around a layout that was already basically set in stone. In my opinion this causes the finished product to have more thought put into it, more charm, more atmosphere, and more history.
Another example would be Fantasmic! They probably could have done much better with special effects, and overall spectacle if they had a clean slate to work with. Instead, they had to figure out ways to implement a new idea into an already functioning and developed area. Working around the limits/constraints of the area, while needing to be extra creative with ways to use what was already in place. The final product is an incredible show that is said by many to be superior to it's WDW counterpart where there was much more space and creative freedom to work with.
This is just my opinion of course, and I know not everybody will agree with me. But, I believe that working around the challenges of DCA 1.0 will be to the advantage of DCA 2.0. The redone park has the potential to be more creative, more charming and have a deeper/richer history than had it been done "right" the first time.
I'm excited to see this park continue to evolve and improve over the coming years. Just as Disneyland has done.