I'm really excited for the Swain Rework, but...
There are some things I think should remain unchanged.
First of all, his ability to heal should remain intact. Swain is notorious for healing and being annoying, and this heal should be able to be used in Zhonya's still.
Second of all, his playstyle and identity as an AOE DOT mage. I believe that his ability to deal Area of effect damage over time as a mage should remain intact especially since there are not many people who can do AOE DOT damage and are a mage. Oh yeah, Swain is the only mage who does AOE and DOT damage, and the only champion who does damage this way other than singed, and Singed isn't even pure DOT. In this way, Swain was unique and still will be if this part of him is kept.