I wish there were modes for Towers

By modes, I mean an option to have them either focus on defense or offense. Such if you were to make it defensive, it would no longer shoot at enemies but rather gain a boost of health, armor, magic resist, and provides a shield for the player (like the second turrets). While offensive mode would have the turrets do what they do now, but also be capable of firing fast as well and delivering much higher damage that scales with level.

This is just an idea I wanted to share since I've been finding towers just downright useless lately.