This is just a bad design. A game should not ask for daily commitment to enjoy what it has to offer.
They ask nothing - they merely reward a choice.
We typically provide some boundaries because, as you've illustrated, something that we allow, is something that can all too easily seem mandatory. That's not what we want, but we do want to provide a reason to come into the game, be in the world, and see what's happening on a frequent basis. It's nice to also be able to offer some rewards for doing that. Naturally, dailies shouldn't be the only way to accrue rewards, and they aren't. Dailies were, in part, a response to a World of Warcraft where there wasn't a lot of incentive to come play on non-raid days, since for many players, the only way to progress became dungeon runs and, for a few, raiding. We also wanted to provide another means of acquiring currency aside from professions, and new ways to acquire reputation with important factions too. They're designed to hit a lot of notes (I'm probably missing some), and I think that they're pretty successful. You don't have to hit your cap, (indeed, one of our fears about a raised daily cap is that players might feel compelled to hit the new, higher cap) but you can if you want to put in the time. Naturally, we also want to continue to add other means of progression to the end-game, and we're looking for ways to do so in a fun and compelling way.
I get concerned when I see players throwing out words like 'bad design'. Perhaps an individual dislikes a design choice, and that's fine. We do our best, but World of Warcraft can't be all things to all people, all the time. That said, making a value judgment about whether the design is 'bad' or not is not only un-constructive, but in the vast majority of the cases I've seen, such an assessment reveals that the design was not well understood to begin with.
These forums represent an opportunity to have a dialogue about the game. I think that choosing words that have context and meaning, and offering alternative solutions, makes for feedback which is more readily useful.