People are talking about tossing fireballs. There really won't be much space for your barbarian/monk/fighter to go and attack stuff without ending their movement in the zone. It restricts where your rogue can go to flank things. It restricts where your warlord can wolfpack tactics an ally to get a flank. The occasional zone is good to have, but throwing around zones all the time, that are not ally friendly can be a big pain. I know I used to want to kill our own wizard nearly every time he used Icy Terrain.
Isn't the zone optional? If not, perhaps you have a point, but if so, it becomes a very useful tool in a wizard's arsenal. Use it in tactical ways where those restrictions don't matter, and all is well.
Sure, you've got fire blasters elsewhere like with the sorcerer, but why shouldn't you be able to build an effective wizard pyromancer?
All in all, I like these new options. They seem reasonable well done, they fit classic archetypes and add something to the game without breaking any real balance issues. That seems the mark of a good article to me.