Maybe every X attacks it gains attack speed for a little bit, or if it hasn't seen combat for awhile it gets a small shield until 10 minutes in. . Maybe make the nexus turrets more scary than an angry squirrel or make the nexus turrets do a aoe pulse something akin to rammus' ult when there aren't champs around. I don't know, but right now turrets might as well be little piles of gold that you click for quick cash. And before you go on about 6 hour long games, do ya'll honestly not have 15 minute or 60 minute games because one side surrenders or the winning team can't pull their heads together and win already?