From what I’ve seen Blizzard is taking a look at older expansions. For example they brought back mana cooldowns on healers and changed mana on hybrids to make mana management more important.
I hope that after looking at Cata they will realize how much more fun it is when meeles have less mobility and casters actually have to cast. In Cata they introduced some intant casts but they weren’t as crucial as now. So there is hope for change. Instead of casting while moving I’ll prefer them to go back to more hardcasting, less micro CC and less mobility.
They say " If old things were in fashion light from heaven would illuminate the flea market"
So no, old ways are not good. You have to adapt or perish. That being said, I don’t say casters should not cast. They should cast while they are moving. It does not mean that casting should be instant.