Bigger keyboard keys on iPhone 6 with iOS 8 I want a default keyboard with bigger keys. That's it. 

No Swype, no SwiftKey, nothing fancy, no other customizations—I just want… bigger… keys. I have thick fingers and I dont want to use auto correct or prediction. 

I know it's possible, because one of the apps I use (CamScanner Pro) has a bigger keyboard (taller) which types significantly better. I am desperate to get that keyboard by default everywhere, or any other third party option or fix that will make my keyboard keys bigger. 

How do I achieve this?

Minuum and Thick Buttons rely on auto predict and dynamically enlarge keys… way too fancy for me: simple, default bigger keyboard, bigger keys. I am happy to sacrifice screen area for bigger keyboard.

[edit - now many months later, I still experience this problem. Over time I have used several apps that offer a keyboard with bigger keys within the app. I don't know how these apps can offer such a keyboard while it is unavailable anywhere else...]
Set your view to zoomed, and change your text size to whatever size you want.  This will allow your keyboard to be bigger and the font to stay the same size.  It does change the size of your icons.