After the release of the S5 for me the only MAJOR changes are the IP67 and Camera. So will you continue with the S series of the Samsung? I mean, do you see your self still purchasing their product maybe until Samsung Galaxy S10 or further. )
I'd have added a "Move to another Galaxy Family" option. In my case, I've gone through an SII, Note 2, S4, Note 3. I'm skipping the S5 for now (like you say, minor changes over the S4 to make it enticing), but I might get the Note 4 if it comes out with IP67 rating. Still in the 'Galaxy' family, just not the 'S' variants.