As one of the designers behind Neat, I like what Zurb have been doing with Foundation, but I'm not entirely fond of their semantic grid framework. Many decisions have left me scratching my head and wondering if there wasn't a better way to do things (innerRow() and mobile[...]() mixins are some of these).
Fair enough. Until we come up with a better way to detect nested columns, I don't think explicit nested rows is the route we want to take. Our primary goal is to use as few mixins as possible to achieve proper nesting.