Veigar Gamplay - The cage is made to surround
Ok Then... Why not make is cage solid (like JarvanIV), remove the stun from the edge and add some effects on his spells when landing inside the cage ?
Something like... Q: Add => When you touch a champion inside the cage, your target is stunned for 1.5 / 1.75 / 2 / 2.25 / 2.5 sec. **w: ** Add => Champions touched inside the cage, take 10 / 15 / 20 / 25 / 30 % more damage. R: Add => When you touch a champion inside the cage, others enemies trapped inside take 10 / 20 / 30 % damage as AOE.
Since the cage duration is only 3sec, you have to predict location of your target to Q+W and profit of spells improvements on both capacities. Or Q... wait for stun... and land W after the cage was disappears.
English is not my native language, so if you have time to correct my sentences, I'll be grateful.