I agree! I think the 7 is nice, but not a ton different than my 6s. My brother just sold his 6s for a 256 7+. I don't know if it is the extra RAM, that awesome camera, or just that 3D Touch works better on its larger size, but damn it is a nice phone!
Yeah the 6S to 7 jump would be marginal, at best. The thing I like best about the bigger phone is the larger Full HD screen. I held off on getting the + variant until the 7 because I used to think it was just too big. I'm now used to the size and I couldn't go back to the smaller phone, tbh.