Never take cleanse. If it must be, take a QSS. Cleanse for a mid champ is a waste of a summoner spell slot. Depending on what type of mid. the enemy is using, Exhaust plus either Ignite or Flash would be a good choice. Have to take into consideration the enemy team comp as well.
Not sure about Liandry. Its a good item, yes, but on bursty champs it really has no use.
I feel as if Lich bane would be a core item item rather than situational. For some survivability and AP, Zhonya would be a good situational item apart from Guardian Angel.