Whats wrong with a super tanky, self-healing and mana gaining birdmanbearpig?
RoA->Deathcap->Rylais + boots somewhere in there. Get a Zhonyas or SV before Rylais if you feel like you need some extra Armor/MR. Finish with a Liandry's. Proceed to AoE snare the enemy team and instagib the other AP mid or ADC, all while taking focus fire from the entire enemy team and not caring.
When I first tried him out I couldn't do well with him at all. Months later I learned a lot more on mechanics. Bought him a couple weeks ago. I wrecked pretty hard. You gotta realize how to pull off combo's as an AP mid. It's seriously what it's all about. How you chain together moves, position, timing.
The only time I have had a bad game as Swain was one where I was camped by there jungler a lot of the time. So much so that both of the other lanes were well ahead because our jungler was ganking each of them.
I finished with 9/6/17 that game and we won in just under half and hour. It helped that our jungler was a friend so we could plan to get the others pushed and I just delay as much as possible. Swain is awesome.
GW2 EU - Gandara --> Sir John Brett - Human Thief, Happy Stromgarde - Norn Warrior, Grizzly Ironstrike - Charr Ranger, Flooff - Asura Engineer