I see what you're trying to say, but I think this will take away a big part of what IS geoDefense and geoDefense Swarm.  It feels like a constant high when you're playing. Constantly placing, upgrading, and trying to think frantically about where to put the next tower.  I think that a pause option would take that away.  However someone did mention an option for the user to manually start when the first wave starts (mostly swarm) which I agree on. 

But I do agree, both awesome games.

I agree whole-heartedly with onewithchaos, the ability to pause the game to place towers would detract from the frantic experience of the game.  I also agree that in Swarm, having the game start paused would give the player time to formulate a level-plan, but from then on the waves would continue to spawn according to the game timer.

I also concur, GeoDefense Swarm is truly an amazing game!!

I completely understand your comments on how this would take away from the game, as I too have that 'frantic' feeling when playing it, and it really does add to it.  However, there are some times that i want to simply sit back and strategize and not be stressed on putting them down quickly.

Perhaps make it a choice in the settings to 'allow pausing and placement' or a concept along those lines.  It could be seperate and not count into the leaderboards under that mode and therefore would not throw the scores off if this setting caused a noticeable advantage.

-Jake