I think a lot of people will do that. I actually bought an IPad mini about 6 months ago (just before this was announced, alas!) because I wanted to reduce the size and weight involved in carrying my early generation IPad. It turned out to be almost as heavy and pretty fragile, for some reason, and there’s now a crack in the glass although I don’t recall ever having dropped it.
So go for the new phone! I’m going to get the smaller of the phones (I think, because I haven’t seen either one) because I have small hands and, being a woman, don’t generally have big pockets or any other place to easily carry a larger phone. My bag is FULL!
I actually bought the iPad because I loved my iPhone 3 but just couldn’t see it well enough so....iPad. The larger iPhone 6 seems like the perfect solution. I carry my iPad around alot. 2 in 1!! Lol