I wouldn't say too much, I'd say the wrong thing. The R tether range is painful for waveclearing under pressure, but I can see why they would want that. While I don't love it, I can't really complain about it too much.
But chill duration... I'm really not a fan of that change due to the slow projectile speed of the E. In teamfights, in situations where you're juggling your E cooldown with Q and R, and so forth, it's a really big hit to your options in terms of how you can combo because the E double damage will simply not be as reliable unless you do a standard E>R (or QE) combo.
Honestly, the way Anivia is right now with thunderlord's and flat magic pen available, it's stupidly easy to 100-0 the enemy ADC in mid game. Like, E>R Ignite easy. THAT, to me, is the problem. Won't happen nearly as much against mid plat+ ADCs, because their positioning is good enough to make that much harder to do, but in lower elos a good Anivia for the elo makes ADCs basically non-existent until late game. Even then they can Q+E to kill, but that's always been true and really isn't unreasonable for her (imo).
What I'd do would be something like this:
- Revert Chill duration nerf
- Decrease E base damage increase by 5.
Sounds like nothing, but it's not. Comes out to 55/80/105/130/155 + .5AP unchilled or 110/160/210/260/310 + 1.0 AP Chilled. That's 40 less damage, chilled, at rank 5, which is noticeable. And we're keeping the R tether range nerf.
-Anivia main since beginning of season 3.