Which is not exactly wrong, if you're a hardcore player who usually grinds rep for hours every day. But as Drysc says, the Daily quests are meant for players who don't have a lot of time to invest all at once. They're meant "to provide greater reward for smaller investments of time." Basically, this is their answer to giving the casual players their own content. Just like rested XP (which is a great idea that rewards you for not rushing through content), the rewards at the end of these "Daily" grinds can't be rushed to by hardcore players who play in huge chunks of time.
When you put it that way, I'm all for it. Hardcore players still won't be happy, but it's there's plenty for them to grind away already-- if you guys have already grinded every single reputation in the game so far that these daily quests are the only ones you have to do, then try playing another game for a bit (I've been liking Titan Quest a lot lately). Some players argue that the casual players expected to do these quests probably won't have the 5,000g needed for the epic riding skill to even start them, to which I say-- err, good point.
Of course the other note here is that, as players have noticed on the PTR, the quests seem to reset every time the server restarts. So if you're really hankering to get to that mount quickly, you don't really have to wait for every day-- hotfixes and restarts can give you a few more quests to do every week.