Tablet/phone sizes are interesting to me. The industry says, "We want to make two or three product lines that are good enough for everyone." That makes sense from a manufacturing and profit standpoint.
The general population laughs because, a) we don't all fit into their neat little sample sizes, and b) the public is going to find uses for the device that the manufacturer never imagined. I read about biologists scuba diving with iPads to do fish counts on reefs, for pete's sake...
Next, they have to walk the line between profitability and leaving behind market share. Apple could make an iPad for everyone, but it's going to cost them in profitability to keep that many devices on the market. Frankly, I see a few too many devices in the iPad/iPhone lineup the way it is.
The next thing is the line between a tablet and a phone. Seriously aside from making calls, what can one do that the other can't - and why is that a thing for a cellular connected device? If I carry a cellular connected iPad all day, why do I also need to carry an iPhone?
For work, my perfect tablet would be a ruggedized iPad Air with the largest memory, a beast of a cellular antenna, integrated GPS, an eInk monochrome screen so it can be read in full sunlight, and a week battery life. For some reason, aside from Trimble ($$$ for outdated equipment), manufactures just don't cater to the outdoor markets. So we make do with iPad Air 2's, Otterbox cases, external battery packs, good database design (to compensate for the sketchy cell coverage), and finding a shade tree to read the screen.
