Making Nasus more interactive to play (against)
I'm sure that I'm not the only person who finds laning against Nasus to be incredibly boring. All that he really cares about is stacking his q, and you've just got to deny him as much as possible. There's often not much real kill potential on him, and while he's not overpowered I simply don't enjoy playing against him. Due to his nature you rarely get any opportunities to roam, nor are you permitted to back early on to obtain an item to pressure him further because any second you're not in lane, you get punished for it.
So what if we turned Nasus' Q into a bit more of a game, focused around the cannon minion? Take some of the stacks he would get off of normal minions, and put them on the cannon. Normal minions give +2 to his q, but the cannon gives +20. (Those numbers result in the overall stacking speed being slightly higher if Nasus gets 4 normal minions and the cannon each wave, but slightly lower if Nasus gets more normal minions)
By applying this change, I think playing against Nasus could become a lot more fun since it would be less harmful to leave Nasus in lane for a few seconds, but you do not want to let him get the cannons under any circumstances. Denying the cannon could open up opportunities for jungler ganks from both sides, bait out Nasus providing kill potential on him, or give Nasus some nice powerspikes if he's behind (Even if he's farming under turret, if he just gets every cannon with his q he's still not completely out).
It would also result in the opposing top laner getting more freedom to roam and try to help his teammates, making top less of an island. "Good, the cannon just died to a minion, I now have 1 minute 30 seconds to tp bot and get them back in the game before going back top."
Riot has repeatedly spoken about giving players good windows of opportunity against enemies, right?