Well, lets take a look at what abilities normal, dire, and legendary animals would get.
Low light vision, scent, blindsight (or blind sense), sprint (though uncommon), ink jet (squids and octopi), and jet (also squids and octopi).
Scent is nifty, and blind sight was replaced with blind sense, which I have heard wasn't that good compared to blindsight.
Plant abilities, which are quite frankly much more powerful, aren't gained until level 12. And I have seen some messed up plants. One of my favorites is the greenvise. Anyway, the abilities given to plants have much more variety and overall potency, as you all know, ranging from the plant type itself (silly power gaming wizards munchkins, type is for the original creature(go trix), to woodsense (almost as good as tremorsence), regeneration (which I am sure was replaced with fast healing, unless they really do want people using shapechange to be immune to everything but clubs and melf's acid arrow).
With the plant wildshape, I can see why they wouldn't allow speacial qualities. I really hope they did something about plants and regeneration (I didn't take a good gander at the monsters in the SRD). Fast healing helps, but didn't they take away heal from druids? Also note, plants don't really get really strong unless you are familiar with above average ones, weird plants from other planes, or the epic mu spore {which, with the new rules, means that even though you will fight one at level 21, you can't become one without shapechange (don't curse me out if you can't, I haven't looked at the new shapechange very well) until level 35, (but by then I would think you would have better things to turn into)} or elder treant, which quite frankly isn't that better, and you have to wait till level 50 to turn into. But hey, thats what nerfed dragon whildshape is for, cuz by then, you can already turn into epic dragons that look to him for tooth picks.
Well, now that I have lost you (we're walking, we're walking), I think that extraordinary qualities should be allowed, but perhaps not immediately. Perhaps when you gain elemental wildshape, you gain "nifty wildshape," or whatever you want to call it. It will let you use all of the extraordinary abilities of any form assumed through wildshape. Heck, if they are giving away supernatuals and spell-likes to elementals (not that they have such a great variety at hand), they should atleast give all EX to your other forms. It might be worth a feat, but only a couple plant forms have the strength to back up that fast heal everyone wants to keep away from our beloved druids, let alone the fast heal...