Just noticed and started reading the news/rumours of the alleged 5.4" 2020 iPhone model, and I am beyond hyped. Where the hell have I been for the past couple weeks? This is exactly what I wanted. This might be the best (and only) thing SE lovers will get in terms of a successor, and I'm all up for it.
I freaking love the iPhone SE because of its awesome compact size, featherlight weight, and capable hardware. If the 5.4" iPhone model ever comes to light, I wouldn't mind the slight size increase as long as Apple doesn't skimp out on the hardware. I want a premium small phone. All Apple needs to do is take the XS and shrink it down a bit.
It's funny, I upgraded to the iPhone X from an SE and as much as I loved the design and hardware of the X, it was just a bit too big and heavy to comfortably use. So I went back to the SE, but after returning back to the SE from the X, I realized the SE was a little too small.
It seems like the 5.4" iPhone will be the Goldilocks of iPhones; not too big, not too small, just right! Now Apple, make it happen!