The mecha designs are quite unusual, as is the fantasy-looking imagery which is a good sign. Beyond that, it's hard to tell how good this sort of show will be just from the trailer - there isn't much room for originality in the mecha genre these days. I'll certainly look into this one a bit further though.
Well, that's part of the point of the anime. It's a bit of a homage to the mecha genre. It's so hilarious, both intentionally and unintentionally, and pretty much sends up the whole sentai team robot genre while still having a servicable plot of its own. I also love the setting and style of the art, giving the world its own character, and the combat is superb in the later episodes of the series. Aquarion is hardly original or strongely plotted, but the way it mercilessly lampoons other mecha shows is inspired.