"Fixing" animation cancelling would be game breaking for every single role.
Those who think that it is cheating should l2p as the technique is simply the optimized utilization of basic game mechanics. I guarantee that every single player does it at least once per fight whether they are conscious of it or not.
It is essential for healers and tanks especially and would make those roles impossible to play if removed.
"Brilliant! Why is it that the people with the most ridiculous ideas are always the ones who are most certain of them?"
The animation cancelling method has to be intended. I cant imagine that they'd give destruction staves such a stupid long animation for light attacks on purpose without a valid workaround.