When I was trying to recruit for a Scott Pilgrim-style game, that was kinda my idea: I love that system just because it encourages you to look at the limit and then break the limit and then break whatever imposed the limit in the first place because there are no rules, deep down. Realizing that from a writing perspective, where you have the time to conceptualize and create, could lead to some awesome pieces of good, solid writing and RP.
The BESM game I was in, the very first, was sadly my longest running as well (I think just over a year or so; real life issues between players ended it pretty fast): we based the entire thing on an Anime, Air Gear, and just went wild with it. Great fun, still remember it fondly.
And now I'm getting all the more excited for a game like this, where we do get to explore character relationships and all the little, piddly details: time constraints kill my stories faster than a brick to the temple, and GMing in real life often makes me feel like I have to be as direct and simple as possible rather than being able to, so say, take an hour to just work with a player on their personal quest (without feeling like the other PCs are sidelined) or allow characters to roam free in a created city (which sadly often elicits the "I don't know what to do")