My mostly uneducated guess is that the keyboard is going to be identical to the Cosmo, and since the case design for the Astro is not complete yet, they just used the keyboard width for the device width, figuring "close enough".
That makes sense. Still though, they have obviously made prototypes. While these probably aren't working phones, there do seem to have working, if not final, "RockUp" slider hinges, and they seem to know exactly which model of screen they are going to use, so I get the feeling they should know the outer dimensions fairly well, except maybe for how thick the battery needs to be. Oh, well, we'll see.
I wouldn't mind if the keyboard shrunk a little bit, because the Cosmo device is a bit too big for my "phone pocket" in my favourite jacket, but I'm sure those who are slightly more well endowed in the finger department than I am would appreciate it remaining the same size.
Yeah. While I can't claim to have "big hands", the Psion Series 5/Gemini/Cosmo keyboard is
barely large enough to let me type somewhat comfortably, which, for a phone-type device is pretty much the best conceivable compromise for me. I recall the 1999
Psion Revo, which was an attempt to shrink the Psion Series 5, and, for me, the typing suffered to a point where I stopped using it. Sure, the ~0.5mm key travel contributed at bit, but it was mostly the shrunk down keys that, rather than being barely large enough, instead were just a tad too small.
Weirdly enough I remember my
Psion Series 3c and 3mx as quite typeable, in spite of even smaller keys. Maybe I just was a slower back typist then, or maybe the "island" design, gave each key enough of a "landing zone", by sharing the space between keys, to stop me from hitting multiple keys. So
if they were to ever use smaller keys, say, to fit more of them, the 3c/mx design might be worth revisiting, but from a sales point of view, I think the current design and size is rather optimal. Some would like it smaller, some would like it bigger, and it looks good.
Btw. out of curiosity, is it the 171mm length of the Cosmo, or is it rather the "girth" (depth and width), that causes issues with your phone pocket?