For my mage it will be a bit of a pain (for a start I'll have to train the higher ranks of frost nova), but i'm sure I'll get used to it.

It will probably make the most difference to play style on my healers. I often have a mid-rank top healing spell for use to top off people when I know they won't take much more damage. On my priest I could use renew (and possibly have that person die to unforseen damage), flahs heal (spending a lot of mana for a hps benefit that I didn't need) or a max rank GH and end up overhealing that person for 2-3k. I liked the choice to be able to cast a lower rank normal heal, so I can top up the right amount of health, in a reasonable time period and for a decent mana cost. I don't raid much on my priest, but end-game raiding isn't the be all and end all of WoW.

With the changes to 5 normal mans (any spec of tank-able class will be able to tank them) I guess they will just dumb them down so the amount of healing needed is minimal, otherwise I don't see how it would be possible for a healer (using max mana spells) to heal a non-prot spec tank without going oom.