260k mastery Nasus here with a suggestion

Could Nasus' ult give flat ad (let's say 40/80/120) instead of %MaxHP aoe damage converted into bonus ad? The only thing I don't like about it is that ulting and getting Hp boost always seems to be at some expense. If you are pushed in under own turret and about to be dove, it damages enemy champion thus aggroing enemy minions. The second case scenario is that when you are pushing the turret and try ignoring the enemy champion with W(Wither) to get a turret, if you want that ulti in order to survive, again you get cockblocked and draw turret aggro. Why? It'd be like if Lulu ulting herself would aggro minions/turrets.