Back to the basics
Look to your competition. Not sure what you're aspiring to accomplish, but the current iPhone app is...far from being a home run. Sure, it's clean. But, it's sterile. You have so much incredible / valuable data and appear to just dump it on a 'sterile' format that makes it unpleasant to review. I compare your app to Canada's The Weather Network app. Rich with data and organized in a clean yet optically / UI friendly manner.
Love what you do. But, in my opinion, something / someone has gone awry in trying to devise a "clean" app.
Don't apologize. I'm in complete agreement. New app has NO visual separation. Huge, yet hard to read fonts don't improve anything. Spreading out info requires scrolling where it used to be on one screen.
The Wundermap is just as bad. Hidden info requires much fussing to obtain and the app default zooms in too close to see any impending WX events.
WX underground followed the Apple model of "Let's change things just so people see that we're doing something!" I believe that all of this is just to bother users so that we're happy when things get changed back (if we're lucky…someday). My productivity has dropped off to the point that I barely touch my iPad (with iOS 7) anymore. I'll stick with iOS 6 on my iPhone for the foreseeable future. This WX app change is one of the 6 things that has kept me from moving to iOS 7.
Sorry for being so curt. Am writing on an iPhone. I omitted a few, "please compare to you competition" sort of statements. I realize I'm coming across as a miserable prick. Not my intention. I truly appreciate Wunderground and supper $. I'm simply bummed out by these "upgrades" that aren't quite at the true "upgrade" status. More like UI downgrades.