Front facing speakers should be standard on all devices going forward.
Cameras will have to be tested before I can make any judgement, but from my experience, HTC always has great cameras. My S3 takes good enough pics, but it's not great. I think all phone cameras can improve. But I agree with HTC not battling the megapixel war, because most of the pics that I take I usually want to text, post, etc and it's a waste/pain to have such a large file.
Signal in my area was surprisingly better with the DNA, so I'm hopeful the ONE will be just as good. Only time will tell.
The one thing I actually missed while using a DNA instead of my S3 was s-voice. Although it's still not great, there are times that speaking a command is much easier. And it's alot more accessible than google voice actions.