It's expensive and nobody has it, for one. I wrote a lot of my assignments in docx and submitted them, and then the TAs and professors were all like "Can you send that again in doc format? Nobody has 2007". BAH! Plus the interface, is annoying. I LIKED the menus.
That's fine, but it's so easy to save it in earlier formats that this point is pretty much irrelevant.
In addition, .docx is supposed to be an office format standard or something now, isn't it? Open Office announced that their new version fully supports it just yesterday, I think.
I sympathize with your distaste for the new interface, since it's not what I'm used to either, but after messing around with it for a little bit, I'm of the opinion that everything is accessible in a much more intuitive manner than with menus. Menus usually require a much more "brute force" search for what I'm looking for. In fact, if I'm looking for a feature that I know exists but haven't used it in a while (or at all), I almost always have to go online to see where it is. I'll grant you that the same is probably true with their new interface, it'd at least be easier to find if you didn't know where it was.
Crazed, if you have access to a server with PHP/MySQL (meaning you or your company owns it; I wouldn't recommend using it on a shared account like dark-wire or something), check out
Horde. Also, if you have to do any sort of collaborative work, MediaWiki is great.