Re: "There's no way to customise this in current software builds: you get what you're given."
My last few phones have had microSD card slots, and to be honest they have caused me more trouble than they have been worth. Some apps will store their data on the microSD card by default, so this causes unexpected results if I decide to take out the microSD card in order to play its music contents through my car stereo, or to put in my compact camera (I have a few microSD > SD card converters on my dashboard).
Please don't get me wrong, I'm not judging you for wanting a microSD card slot, but the point of my post now is to highlight the disconnect between my desire for a microSD card slot and the reality of actually trying to use it - especially between different devices. Oh, and on top of that I lose the damned tiny things.
For sure, if I did a lot of commuting and was in the habit of watching locally-stored video on the train, then for sure a nice big microSD would be nice... but really, it's best treated as built in storage once it's fitted to the phone. And for watching video whilst seated, it isn't a chore to use a microUSB thumbstick. If you want a microSD card in order to swap data between devices, then you have to sacrifice having the card's data encrypted.
So, for the above reasons, I'm curious as to why people demand a microSD card slot instead of just a phone with reasonably-priced ample storage to begin with. However, the above might give a clue as to why microSD card slots are falling out of favour with phone vendors, in addition to being able to charge mark-ups on storage, of course.