What would rock is if the client, or even just a very stripped version of it,
could be turned into a browser extension which could create a resizable
mini-window that would force website content to flow around it. Kind of like,
I dunno, mud-in-website instead of picture in picture.

I'm kind of sleep deprived, so maybe this isn't as brilliant as I think it is,
but it seems to me the ability to have the game window open in the corner of a
browser, without it hiding website content, would be pretty snazzy. I THINK
this is entirely doable, but I'm not an expert on these matters. To the best
of my knowledge extensions can control the flow of website content, gain focus
when the mouse is over them, and do the other things that would be needed to
make this work out. Double click for fullscreen etc, have the fonts shrink
based on the window size and user prefrence...it'd take some work, but it'd
bring lots of players I think.