Exactly this.
If they just dumped all the Skyrim details, it would quickly become yesterday's news.
By releasing a steady trickle, they are able to keep on the front pages of blogs and gaming magazines.
This, it's just marketing. If they told you everything, it'd be no fun anyway.
Also, they don't want to release info if it's not certain. I was actually pleasantly pleased with Todd's straight forward answer about horses.
Also, saying "pleasantly pleased" is redundantly redundant.
check your email spam box. bethesda has been sending me pics and videos galore including lots of gameplay footage. i have to say that im pleased with the changes to the argonians. and as for the khajit feet.........well im sure everyone knows about that already. there is even a quest involving a midget, a unicorn and some butter.
Funny enough, in my spam box contained an add for butter.