Web: Nicer on the bigger iPad but still great on the mini.
Comics: Undeniably better on the bigger iPad
Netflix/HBO: Bigger screen, bigger movie. Advantage bigger iPad.
Gaming: Touch only games I would say it's a wash, but games with on screen controls work better with the mini due to its smaller and lighter form factor.
It might just be 2", but that's on the diagonal the difference is about 30%+ screen size. It does make a difference in person. My best advice is the test both in store and make a decision, I would say go with the mini before (the weight difference was massive) but with the iPad Air being 1lbs it will make a big difference in prolonged use vs. the 1.4lbs iPad 4.