I'd argue detecting iPad 2 in landscape mode would be an opportunity for an extra RHS column
While on Mini, you'd just drop that
Shame we can not have that possibility, as the extra 19% of screen makes an extra column readable.
It's the nature of things, and should not be an issue if the responsive design is done properly
This is if you believe in non-zoomable design. If you allow the user to zoom, one option would be to deliver full desktop design and content, as you prefer.