RoA is totally necessary on Swain, the heath mana and ap are exactly what he needs. Also unless u plan on having a lvl 1 team fight torment is a better first skill as it will cause the enemy to take more damage from your auto attacks for 4 seconds as well. And please never buy mejais unless youre just ip farming. It is a global taunt and is almost never worth the gold.

U get my +1 however, there is alot to be changed. Nevermove should not be your first talent, as even if you have it you can't do any dps. Also change ur mastery tree for the improved ignite and flash. 0.5% more damage won't do anything.
another thing to mention is that you do not need rod of ages, you have enough mana from your passive if you last hit well, and you have your ultimate to heal yourself. buy a mejais instead.