Even without pushback, most melee classes can either:

1. Stun you, blind you, fear you, death coil you, cyclone you, sheep you, or in some other way cc you, ending your cast
2. Interrupt your cast using counterspell, earth shock, spell lock, silence, kick, shield bash, ending your cast and locking out that school/silencing you
3. Run out of range (maybe a new use for sprint?)– btw, this is the primary reason I find fireball useless in pvp.
4. Back up and charge/intercept (warriors/bears)
5. Break LOS
6. Take half a step forward and get behind you just as the cast is going to get off (while mysteriously swinging a weapon that hits you anyway…?)
7. Vanish
8. Cloak of Shadows

Any of those, and a failed cast results, leaving exactly ZERO damage (and since there is no reliable autoattack for casters) and leaving the caster to have to decide what to try next.

Reducing or eliminating pushback will really only dramatically affect the situations where you have one person at range and a DIFFERENT person in your face. That and hunters, who are OP against casters anyway, if they ahve the sense to get a fast attack speed pet and spam arcane shot.

Bottom line:
Pushback or not, a long cast still takes a long time, and is not that reliable anyway.

I also consider it to be a Rogue nerf. Major rogue nerf. You can’t stop me from fearing you forever! We’ve got a fighting chance now.

Now, if only warrior’s charge stun didn’t take effect until they got to you (instead of when they start the charge)…. If I kill you before you get to me (or charge-stun you with my demon, or get a death coil off in that split second, or step out of LOS before you get to me, or…), why should your stun work?