8 or 16 is plenty to cache a few playlists, videos and books and magazines for offline use. Definitely enough to get anyone through the day or a long trip. With enough room left for some games and to take pictures.
I have a 32gb sd card in my Evo 4G LTE only because I got it for a few bucks on an Amazon lighting deal. I'm using 0mb of it. My 16gb Nexus 4 has no sd card and I have not had the need for one. Some people might have special needs, but it is not the norm.
On the battery front, batteries are large enough and efficient enough that sealed batteries are largely not a concern for most consumers. Again some people may have special needs, but not the norm with batteries these days.
On my G1, with 1Gb and a 700mah battery, having a 8gb sd card and extended battery was important to me.
iPhone users have been getting by with 16gb and sealed batteries for 6 years and they aren't complaining and they don't have as many cloud options available.
Some people might need the extra space or extra batteries but for 98% of smartphone users they can handle it just fine. And if that means that devices can be engineered better, look better, feel better and work better, then I am fine with that. The Nexus 4 and HTC One are beautiful and solidly engineered devices that I would take over Samsung garbage any day. That's just my opinion though. You are welcome to have yours, but you are not speaking for the majority.