>Is there something I'm missing? Is this just a local maxima where you'd look back on and feel stupid for not seeing the "obvious" improvement path?
A handle. My hand is not L-shaped. Make it hand-mirror shaped and shift as much weight as possible into the handle. Preferably a fold-down handle.
A folding screen. Or rather, two screens with a hinge, no need for fancy flexible screen tech. It doesn't matter if there's a visible bezel between the screens, you're only displaying text. Ideally, you'd cram it just small enough that it can fit in your pocket when folded.
Also, once you have a handle you don't need bezels.
A handle is an interesting one - I'd be a bit worried by having that you'd make it so you can't hold it any other way. As I read I naturally reposition my hands, sometimes both on the device on each side, sometimes one gripping the side. Sometimes my thumbs supporting it from the bottom, sometimes the thumb over the top corner. It's light enough you don't really need that much "grip". Sometimes not really gripped at all, but leant against sometime, like my hand or the back of a seat tray table on a train. I do the same thing with paperbacks.
I can't imagine holding a hand mirror for any length of time comfortably - especially if there's only a single orientation you can grip it with the screen upright - but that may be the weight distribution as you mentioned.
Folding would be useful for putting it in a bag or fitting it somewhere, which hasn't really been a big issue for me. A flat profile is already fine when putting it in a laptop bag - it's thin enough it just slides down the side of the pocket. I wouldn't be surprised if decreasing the total volume is pretty much at it's limit already with being able to be held - but maybe putting that is a more square package when stored would be easier in some cases?
A handle. My hand is not L-shaped. Make it hand-mirror shaped and shift as much weight as possible into the handle. Preferably a fold-down handle.
A folding screen. Or rather, two screens with a hinge, no need for fancy flexible screen tech. It doesn't matter if there's a visible bezel between the screens, you're only displaying text. Ideally, you'd cram it just small enough that it can fit in your pocket when folded.
Also, once you have a handle you don't need bezels.