This isn't limited to just smartcast. They totally screwed up the feel of playing her and made her super clunky, IMO. Even when not on smartcast, you cannot cast the spell at all if your pointer is outside the max range of the spell. Instead, Anivia walks forward to where she would be able to cast it to that location. By the time she moves forward to throw the spell, and then the spell actually gets to that target location, the person you were throwing it at might as well be in a different game already.
They also completely removed the basic max range indication circle that shows up any time you hold out a spell without actually casting it. I use this all the time for a quick visual check on the range I have where I can cast something. A good comparison for how it should work for this is Jarvan's flag. It shows an aoe indicator where you would place it, but the center of the aoe circle is locked so it cannot move beyond the casting range radius. But in Jarvan's case, the casting range indicator is at least still there.
She needs to go back to the drawing board and have the rework reworked so she actually feels smooth to play again.