The concept is interesting. I've been watching Mahoromatic lately. I'm not sure about removing the time limit concept. It's been one of the key things that's seperated this show from your run of the mill maid series. I like the idea a lot, as it expresses that her time is limited, and leaves you wondering how far they'll take it. Remove it, and you have a maid show with some combat thrown in. I have only seen four episodes, but the concept sounds like it removes some of the depth of the show.
I ake check this out after I've seen more of the series.