Zonya's is the most op, bs in this game I hate this item with a passion. You know what Mages i'd prefer it please, get an ap item with a shield instead please. As a yi main that one item means I can't touch you (same with any other diver or bruiser or most) now when a team fight starts I can only go in on the adc, theres very rarely a time I can touch you since you'll activate it, your team will kill me and that it, nothing I can do, in a 1v1 use your spells zonya's if your team doesn't come my ults wasted and I'm forced to back off because you have your cooldowns back. I hope to god rito listen partly to what you mages want and give you a maw and get rid of zonya's will be the best day in years.
Anyway though, the point is, assassins have a hard enough time in lane and forgo the stats they want (armpen) to survive early where you out scale them anyway. No assassin even wants to get maw, most aps will build zonya's if needed or not at some point assassins would rather not have to and many don't anyway unless they are behind becasue they want to rush duskblade