Penetration changes made Haunting Guise powerful, and it finally has an upgrade that's why.
How about this then? Nashor - Lichbane - DFG - Rabadon - Malady - Sorc.
You get penetration, you get MS, you get AS, you get on hit bonus, you get CDR.
All you leave behind is 300 HP and Liandry Proc. Seems better to me.