How odd then. In my case (7.0 LTE) it's fine. So your gmail account works fine in the gmail app but if you set it up in the SEPARATE email app it gets stuck on Loading? But that app works fine with other mail providers? And do you have any other Android devices where the email app currently works with your gmail account?
I just reset a Gingerbread device and its email app still worked great with a gmail account. So *if* this is the first device you are trying to connect to your accounts, go on the gmail web site and see if....IMAP mail is enabled. Because I think the gmail app on Android no longer uses POP3 or IMAP but rather a google API. And if IMAP is not enabled for your account, most other mail clients will not work.