I think it's not as much about size as it is weight to a point, I remember the problem with my Q5W is that it was like a small brick, both in bulk and in weight. If something is a bit larger but light, it's less of a hassle than something smaller and heavy. Not having a hard drive will help this a little...Probably still heavy though.
Still, the supposed best portable rig up until now has been the H120/140 + D10 combo, and that's much larger. Most other setups that deliver SQ in that range are around the same size (And some much larger, don't we have people that carry around lisa IIIs here?

) And that's just people with PDAPs, those PCDPs are heug, man.
I still don't see why people are arguing space. Obviously if you post on head fi at least every few days, then you access a computer every few days. Do you listen to enough music to get through 64gb before you get to the computer that you keep all of your files on? I don't think many people do this, and the few that do should be willing to carry around a spare card or two. You also have the fact that you cannot listen to 64gb of music before the battery dies, so you can just swap some music while you are charging it.
Let's see what else, something was said about tagable lossless formats, I would think the GUI would be more of a cowon 'organize by folder and file name' style than a ipod 'organize by tags' style, it just seems to fit the format better. Then again he said the GUI would be like an early ipod.... I don't use tags for anything except last.fm myself, so it wouldn't matter much to me, but I can see some people having problems with this.
Personally I like the idea of a stationary DAC. One can argue about the whole multitasker bit, but since I don't own a uber expensive DAC, and it looks to be better than what I got now (see sig broskis) then I got no problem with it. I would think that it uses that DAC for portable use anyway, so it's just making it capable for stationary use as well rather than it just sitting there doing nothing when it's being used away from a separate source and only for non-portable use.
Price is about the only thing that someone can argue against it (In my opinion at least), but then again it's not like you get twice as good SQ from twice as expensive headphones, or amps, or DACs, or cables or any of that, so it certainly shouldn't be expected for PDAPs, the way I look at it, is if it's better than all other portable setups, then 800$ is not that bad. Still 800$ I don't have, but it's 800$ I would be willing to spend.