That's true but I think people prefer freedom rather than usefulness.  For example, before people wanted a pathless geoDefense, and David did an amazing job at making a game with both elements, puzzle and pathless.. However the freedom you get out of a totally blank level is what really attracts people, I think.  Maybe its not so much that people will be super creative, but hey maybe some people want to have a million shock towers with lasers/missiles, I know for sure I would like a totally blank field to mess around with thumpers.

Another thing that people are forgetting is the creep release, the "home base", and the obstacles (healing/speed hexagons).  Rather than a blank field, a level editor would be much much better. In fact I would pay extra for a level editor, that should be what people should be asking for. The ability to place your own home base/number of lives/creep exits/towers/obstacles.  And I'm not sure but it seems that a level editor would be better implemented in this game because of the hexes as opposed to the first geoDefense. 

The thought of a full circle of star creeps homing into a one star base is totally stuck in my mind now. ;b

that is easier said than done; you still have a finite ammount of money, and have to build up to that point along the way. Plus, you also have to consider that there likely (certainly?) would be pulsars, so that also changes things. Throw in the fact that you also want to not just kill the creeps, but kill them close to the exit (for the multiplier bonus) and you have a much less predictable experience than you think.