I like a smaller screen. Like most women, the thumbs just don't reach easily. Take this test and give it to a couple of women. (I'm not affiliated lol, it's the wsj).
(The phone examples used are outdated, but the measurements are interesting.)...
Re: APPS to SD Card
The updates are the problem. I've been putting apps on my sd card for years (still have my galaxy s4), but when the apps update, they move back to the device storage. I then move them back to sd.
Any phone would heat up when playing graphic intense games. Also if the game is not optimized by the developers, it would take some extra load on the device.
And 60C is normal temperature when playing high graphics games. And 40-50C during normal use is absolutely normal.