I don't have an iPhone, but I just can't understand why the keyboard cannot be lowercase when you're writing in lowercase. I just don't understand the motivation.
The original reason for that was simply because they hadn't thought of that. The ongoing nominal reason was that it was a continuing nod to skeuomorphism. But given Jobs' passing, and the otherwise massive ditching of skeuomorphism since then, I do not begin to understand myself why that's the still the case. I'll hope that iOS 8 might introduce that mode as we get closer to shipping.
Long tap for numbers and punctuation, ala android, is always annoying missing when using the iPad keyboard. Its so simple, plus saves so much time and mental processing hunting through the extra keyboard states.
I don't understand why every single keyboard on mobile doesn't have the .COM button. It's basically become as ubiquitous as any punctuation mark given how often emails are typed.
IIRC, this is exactly what happens for html5 forms: the default keyboards on ios/android/wp do display the "@"/".com"/".net" buttons next to the space bar depending on the input type.
I'm glad it doesn't. WebOS does this, and I find it jarring to have the entire keyboard twitch every time I hit the shift key. I much prefer Apple's approach.