So first things first, new swain looks awesome!! The rework seems like it made swain interesting and possibly relevant (we'll have to wait to see that though).
That being said its also a little bit of a dissapointment. If it was a new champ it would be just cool but for those of us who are used to the old swain we know that the reworked one isn't the same. The playstyle, the skills, the looks everything seems diffrent, other than the fact that they both (kinda) use ravens.
And that brings up a more general question about Riot's attitude towards reworks : How far can you go (with changes) when reworking a champion?
Some examples of good reworks are evelynn and warwick. Even though they went through major changes the didn't lose the aesthetic that made them what they are. They kept basic aspect of their kit but made them relevant with the game. The visuals also didn't go through major changes they just got much much better.
And that is in my opinion the (major) flaw with swain rework. It didn't keep the swain feeling!
In coclusion, new swain seems awesome but I think I am gonna miss the old swain a little bit (something that won't probably happen with old warwick or eve).