Veigar's cage has a slight warm-up time.
So when it starts to come up, you can escape with Akali's dashes, sometimes even hit him with the ranged attack and wait it out before re-engaging.
After you bait out the E, you can live on his face so long as you dodge the death from above and keep your health up so his ulti will not crush your face. :D
Also, Veigar /has/ to stack. So if you can position yourself correctly, you can sometimes get in free poke when he uses his Q to pick up minions for stacks.
It is minor, but it can add up. This can also sometimes lead to him trying to use the cage to trap you, which can let you all in him pretty well or at least dive on him in response. If you can do that, it can be easy to get a flash out, or at least some good damage. The W is pretty easy to avoid once you get used to it.