@Riot: While you're changing Nasus, have you considered his E?
Spirit Fire's huge amount of flat armor shred is out of place on a Juggernaut like Nasus. It has two negative side-effects on the champion:
- All that flat pen means Nasus is much better at killing squishies than tanks, which is counter intuitive for a Juggernaut. Juggernauts should be happy to hit tanky targets, even if they'd rather be slaughtering squishies.
- It also means he spikes hard in the mid game but starts falling off late as base armor values increase and enemies buy armor items. For a champ whose core fantasy is "hyperscaling Juggernaut" it's pretty weird to spike at 25 minutes.
You could change both of these issues by switching E from flat armor pen to % armor reduction. Maybe make it reduce enemy armor by 10/15/20/25/30%. You'd probably have to make follow up adjustments to the numbers but this would really help Nasus fulfill the role of a late game Juggernaut, without unbalancing him.
EDIT: To be clear, what I'm talking about here is a neutral to positive change in Nasus' power level. It's by no means supposed to nerf him, I don't think he's too strong, he's actually underpowered at the moment.