Well for me my wish list is as follows:
M7 Size in the M8 design - I love the feel of the M8, rounded edges and all but it could stand to be a tiny bit smaller. Hopefully without having to sacrifice too much in the way of screen size.
32/64/128GB - It's really time for this device to truly compete with Apple and having devices all the way up to 128GB of storage helps with that.
Keep the MicroSD - This just supplements the on board storage and gives people more options, sure most won't need it but some of us do and appealing to a larger base is needed for HTC.
Wireless charging - Not sure how this can be done with an aluminum device but I don't believe anything is impossible and it is really necessary.
810 Chipset - This really is the only thing that is acceptable for a device that will be a "flagship" product.
3GB Ram - Same statement as above.
Camera - While the ultra pixel concept was good on paper it just doesn't work. Time to get rid of it and go with a traditional high pixel camera. 16 is the minimum but most leaks point to a 20MP which is better.
Bezels - minimize them all the way around, get rid of the dead space at the top and bottom where the logo is. There really is no justifiable reason for big black bands at the top and bottom.
Screen Quality - Like others here I don't know if that it needs to be 2K, 4K, or whatever. Current screen quality seems good to me but the industry will drive this upward regardless.
Water Proofing - This is seriously overrated and would rather they concentrate in other areas.
Sound - Front facing speakers are the standard now, I'd like to see a little better quality in the next version.
DevEd - Expand the developer edition so that it includes options to include Verizon and Sprint and not just GSM providers. I hate buying branded devices from carriers and would prefer to have fully unlocked factory devices. Doubtful that it will happen but hey I can dream.
Sense - I am apparently one of the few who like Blinkfeed but it also doesn't include enough sources of information that I like. Conceptually its great but still needs work. Also would like to see more advanced options available to alter the colors and backgrounds. Right now I do that with custom ROMs but those tweaks should start being included in sense.
Ok that's my 2 cents...
PG