Sekirei is an inoffensive manga that has the mistake of being overly ambitious. It suffers from juggling between way too many topics, genres, and characters. As a result, most developments end up being sloppy, overly simplistic, and disappointing. These include, but are not limited to, the action and romance.
One of the few things Sekirei does have going for it is its amazing pacing. There's a fantastic rhythm and balance between arcs to keep you on the edge of your seat wanting more. That is, until it is interrupted by all the yappings about the manga's setting. It is needlessly convoluted, confusing and just creates so many dues ex machina moments and problems that are out of this manga's depths.
Despite that, the premise is great. What little romance and drama there are was executed beautifully. The slice of life and comedy are arguably the best parts about this manga - although there's less of them as the story goes on. The dynamics between the main cast, and some individual characters, are perfect for the story it's telling. Also, who can forget about the awesome closing volume?
I believe Sekirei has more good points than bad, however, it's unfortunately a flawed manga that requires too much suspension of belief to be at least decent. But I still personally love it - especially its (albeit basic) core theme about love in its freest form. Also, bonus points for being a manga in 2004 Japan that includes multiple gay relationships and even a genderfluid character. Even though I don't think the author meant for it to be anything meaningful - it's still pretty great to have include these elements. Thanks for the scanslations!