[barlescabbage]

Um, no. You can't change the apple ID email if you're using apple's email. I ran into this problem myself.

I signed up with a nickname email when I was younger. For example [e-mail]. You can later make an alias like [e-mail]. But every time you sign into iCloud, or write a new email on your phone, it's gonna default to [e-mail].

It is a really bad issue for people that use apple's mac email exclusively.

And I can sympathize with the article. If you're divorced, and you change your name, you have to sign into iCloud with your ex husbands name every time you sign in or send a default email. You can't change it.

[huxley]

You definitely aren't stuck defaulting to the email address for iCloud, I just switched the default on my iPhone, if that was ever the case, it isn't in iOS 8:

Go into Settings/iCloud/Advanced/Mail

You can then pick what email to send from and it lets you pick the default email address to use. Click Done and it's switched.

The support article I linked to is misleading if you can't modify the Apple ID login if you use a .mac/.me/.icloud email address and would definitely be a bad hassle, Apple should allow the user login to be changed.