I kinda enjoyed my time so far on hardcore.
I got to 5k Favor and got my wings, and now that I got what I was aiming for, I am finding that I am very unmotivated to continue. The hounds were scary at first and at low levels, but as I got higher level and better gear I was able to solo a hound if I had to, though I had to watch my hp.
I will agree with everyone that the hound mechanic of showing up every so often was quite annoying as I have to take work calls every so often and I couldn't just kill everything around me and then take a break.
I liked the idea of the hounds, but past some point, they became more of a nuisance to me than true danger unless I wasn't at my computer for whatever reason. They just limited the number of people that got past level 5, and so limited the number of people past 10 by even more than normal.
I will add my 2 cents for a future hardcore to step away from the perma-death idea. Maybe (and this is stolen from someone else I saw on the forums) insta kill everyone in a quest if anyone dies, and kick them all back to their bind points. This would let them drastically change things up or raise the difficulty without it being quite as punishing as it currently is (losing hours and hours of work because of timing a trap wrong or getting lag in the wrong spot or going swimming in sharn lava by accident). Could even add more things to make soloing and piking less viable if that's the desire.