just had a idea about swain and tried it out

god I was so unkillable. I just ran into the enemy team and chased after the kalista ori and lux. I would take every single ult and half the time still get out alive because I had a huge shield from AAS (boosted by 10%) and all my heals from ult and gunblade (boosted by 35%) on top of redemption active (bosted by 35% as well)
also had ghost flash and stormraiders... they wasn't getting away or if I had to run, they wasn't catching me
, as it gives mana and CDR for more damage. It would reduce your sustain but give you more damage and a bigger shield for your seraph's embrace. Hextech gunblade really only works in the early game with the attack damage.