To some people, 10inch is too big and 7 inches might be easier to hold in their hand. Between the iPhones 3.5 inches and the ipads 9.7 inches, 7 inches might be the sweet spot. I myself am perfectly content with the current size 😀
I don't get it either. Why create another thread regarding the size of a proposed, non-released, highly rumored device instead of joining those already in progress?