Remodeling the old world and making it playable again was something the fans have been asking for since TBC released. It's not like they are just remodeling skins and shit, they are doing a pretty thorough change of Azeroth.
The 5 levels is probably because they plan on releasing many more expansions in the future, and they don't want to keep making the level cap go up and up.
TBC didn't have a new class, just two new races. This expansion introduces two new races again, but also allows old races to pick new classes, which you can either hate or love, depending on if you give a shit about the lore.
Where is this info about no new talents? If they are adding 5 more levels, I'd assume they would have a few new talents. I stopped playing WoW like 8 months ago, so I've just barely kept track of what's going on with Cataclysm.
Also, the new profession does sound a little lame, but oh well. As for the dungeons, it's not that many less than what Wrath shipped with, and more will unlock with patches.
You are focusing more on what they didn't add, instead of what they are changing. This new expansion isn't supposed to be about more levels and dungeons, it's all about them attempting to make the old world playable again. Giving a reason for people to actually come back to Azeroth now.
I think compared to Wrath and TBC, this expansion sounds the most interesting, because of how much I enjoyed Azeroth. But, at the same time, it's such a drastic change, it's sort of alienating any new players that may want to get into WoW at this point.