Honestly the changes didn't hurt me when I play Anivia. I honestly never liked Athenes on Anivia...The CDR just doesn't feel like it has much impact to really justify buying it (with the wall being the only skill over 10 seconds, CDR feels practically wasted). I've always rush Tear into RoA and almost never run out of mana with Anivia. After your Tear and RoA is stacked, if you can get blue then you honestly will never run out of mana...Hell some times I'll even tell my Jungler that he can have blue if they're playing a mana based champion as well.
Then again the way I usually build her is a bit on the tankier side.
Tear
RoA
Rylai's
Liandry's
Sorc Boots
Whatever you need for whatever situation. Usually either Rabbdon's, GA or even a Warmog's.
As far as "Viable" goes...I still think she is very strong and the fact that she is so rarely played, it's easy to win lane because people will always underestimate you or just straight up not know how to fight Anivia.
Also Teleporting Egg is always fun and it's always a good laugh at the reactions you see from players who have not faced that before xD