I agree completely. Give me a 64GB+ phone and 2+ day battery life and we can talk. Until then, I'll keep on insisting on a removable battery and expandable storage. What's more, its hard to ignore the fact that the one company making Android phones with removable batteries and expandable storage is also the one company making all the money selling Android phones. I don't think that's a coincidence. I think its an expression that Samsung is giving people what they want to buy.
What's more, I think your argument is flawed anyhow. I currently have a Galaxy Note 3, and the mechanism for the attachable back cover takes up almost no space at all. I just don't believe that the space taken up by the handful of clips has caused the internals to move so much that they had to shrink down the battery.