Can't think of any reason to upgrade personally, except if you have use for the additional dictionaries (French, German and I'm not sure what other languages).
I haven't found that the maps app was that awful, although it's far from perfect. But then I rarely use it, so my opinion is not worth much. It did send me in the wrong direction once, but I doubt that Google Maps would have done better in the same circumstances. For some reason both apps (and Google Map web app) cannot find the train station nearest my home. It's on the map but keyword search doesn't find it.