I think the minis have a 5.4" screen, meanwhile the SE has a 4.7" screen. I own and prefer an SE.
>I do miss smaller phones, and especially a physical keyboard.
There's these "Clicks" but it's a rubber slip case that has an extended keyboard at the bottom. They're pretty hideous.
I also wanted a physical keyboard, so I waited and found on EBay a Moguls Mobile iPhone 6 Keyboard case, which actually fit the SE after I dremeled-out the camera hole a little! My rose tinted glasses were a bit strong though, because swype is faster than thumb physical qwerty.
I fondly miss when HTC was making innovative devices, when everything was up in the air. I had the G1, a mytouch4g slide, A Samsung Galaxy S relay. All QWERTY slider phones and all amazing experiences.