The Constructor class needs some tweaking after I was playing.
Give the Constructor a speed boost along with the spawn shield. It's near impossible to get away without deploying your ONLY sentry.
Regenerating Sentry. the rocket sentry needs the regeneration power the others have. You are useless once your sentry is destroyed.
Remove the Sentry's self damage. there are too many careless players that walk directly in front of a player's sentry.
Push Brooms. It would be very nice to be able to push sentries in and out of battle for safe repairs and to move locations.