I hate to criticize before the phone is out and is put through it's paces (maybe a second camera can, as the manufacturer claims, improve overall image quality in the sense I'm looking for), but a higher resolution / MP count / ability to zoom on the pictures is kind of a deal breaker for me. I've had four HTC phones in a row now. I even convinced my wife to get the One last year, and the only real drawback was the camera. I get what they're going for, but we don't just look at our pictures on the phone, and some gimmick-y after-the-fact Instagram effects on the 2014 version are going to deter me, not draw me in.
As for the microSD cards - until all the carriers offer the maximum capacity versions of the phone, I need the card option. Sprint has been getting beat out by AT&T lately and only offered the 16Gb versions of phones for the first 3-6 months after launch. I can manage apps and OS on that, but I need more than, say, the remaining 8Gb for media, and I'd rather not put ALL of my eggs into the Google basket. That said, they do get more of my eggs than any other single company out there.