Idea for Wit's End buff (just throwing stuff at the wall)
What if Wit's End gave health, MR (maybe it builds out of Spectre's Cowl?) and attack speed, and makes your basic attacks do bonus magic damage that scales with a tiny bit of your max health? I mean, the only people that really like that item (or used to, anyway) are bruisers that like attack speed (Shen, Warwick, Volibear, Shyvana?, idk who else) so maybe this would be a decent buff to the underused item (and sort of a comeback for Atma's if any of you miss that item :p). I'm not sure if it should still sap MR or not if it acted this way though.
Tell me what you think! This idea literally just popped into my head. 
EDIT: Added Voli :p