Like many I held out hopes for Scribblenauts being revolutionary, but I think the big problem is it didn't learn the lessons of its predecessors, the text adventures of old.  Put succinctly: Scribblenauts got the nouns down.  What it forgets is the verbs.
 
Parser commands in those old games were difficult because they not only had you worry about nouns (that were, granted, already in the game world in some fashion, not summoned by the player), but also about how you could interact with the environment, other things, things with other things, and things with the environment.  Lots of combinations to work out, and eventually you just had to hope people wouldn't be so lacking in creativity, or too creative, to get themselves stuck.  Some of the puzzles were deliberately diabolical ( Douglas Adams' games spring to mind), but other times it was a function of the game makers and the game players sometimes being in a different mindset.
 
That different mindset is dangerous if you expect players to play a game fluidly.  While you can expect some stumbling blocks in a game so ambitious, it seems like Scribblenauts wound up letting the actions that objects and you can have with the environment go by the wayside, and it apparently suffers for this huge oversight.
 
Others aren't so rash as to ignore the power of the verb.  Veteran game creator Chris Crawford is working on a system that seems more like a build-your-own-dialogue box rather than set choices.  It's sort of like a hybrid between the old, unmanageable parsers and the staid dialogue options we often get in RPGs now.  Take a look, I'm hoping more people will capitalize on the power of this idea, as it may finally help bridge the gap between immense player creativity, and a designer's limited means to harness it.
 
The openly licensed system is available on the project's main page:  

http://www.storytron.com/