I tend to agree with mold

600mb is most likely an exaggeration, but for many out there with broadband, a download of that size is a drop in the bucket.
And if you're still on dial up, well, a CD could be mailed to ya.
Just sayin' if HTC is purposely keeping it down for that reason alone, then blah. There's plenty of room to inflate. HT does wonders with code and keeping the size down considerably, but if sacrificing size means easier coding and/or for throwing in other neat effects, then by all means, increase the size. I have a large HD thats waiting to be filled [with other material besides pr0n].
Of course, that ^ is all speculation. I'd like to know HT's take on the matter. For now, I could go either way... Curly can also be correct.