MMOs have spun around where most players don't play parts of the game for fun, they play it for stuff that benefits them. Not all, but most will not do anything more than what gets them the carrot. Look at the official forums (put on a hazmat suit first though) and you will see a bunch of posts from people who basically say, 'I only log in for 3 hours a week now because that is how long it takes me to farm my weekly cap for tomes.' The same people that complain about having no endgame, the same people who don't want to waste a single minute in a dungeon speedrun, the same people complaining about no content.
There is content galore in this game, but people choose not to partake, or to blow through it as fast as possible to 'win the game - be the best.' Once a day you can run a lowbie dungeon for a token amount of tomes won't do anything than create a situation where endgame people finding the quickest way to burn through that which will then lead to that being the standard on how to run those dungeons. It will also usher in another source of gear discrimination for speed runs. Maybe the once-a-day thing will allow it to not be as pervasive than having it always on, but looking at the trends already in the playerbase tells me no (as well as the Magic 8-ball).
It's a nice idea, but I can see it becoming something completely not nice once the community is allowed to twist it around.