Hmm...
My thoughts having played from well before launch during closed beta all the way through to a few months after (once they finally let people buy and play the damn thing...) then again several times since then...
The combat and skill system is shocking. While it promised to be open, free, let you be what you want... it's really not like that. You have to have certain skills. You have to play a certain way. It's just as restricted as any other MMO only with less reward as there is no real progression. That combined with terrible hit detection, archaic net code and some very poorly thought out mechanics makes for a rather bland and in some cases down right depressing experience.
PvE is a waste of time with terrible AI and little meaningful reward. The world is beautiful but devoid of anything of interest and takes an age to traverse. Gathering and crafting is mind numbingly boring and the economy is shot. All of which means there is nothing to do when not many other people are around. When there is other people around then great, lets fight. But the alignment system is non existent, there is no real risk, no true reward. So what's the point?
They have added many things and fixed many bugs. But the game is still the same. People always say "it's a different game now" etc, etc. It's not. The core issues are still there and always will be as they are design flaws, not bugs or missing content. What makes it worse is they release a medium sized patch and call it an expansion... kind of like they are bragging about adding stuff that should really have been in the game before it launched, not over a year later.
To top it all off the UI is terrible, the client is not exactly the most stable or quickest around, it's full of idiots and is quite expensive.
Darkfall promised to be a fantastic game. I followed it for years in anticipation, even forming a 100+ strong clan to play it with. The day we got into beta though, I knew it was all for nothing. It turned into one of the biggest let downs ever and it will never be what they said it was going to be. Shame really.
As for comparing it to UO... they specifically said they were aiming to recreate what was great about UO without the dodgy bits. They based their entire game on UO. Sadly they got it the wrong way round. Just like WoW was based on EQ, etc.
It has failed in terms of what they said they were going to deliver compared to what we ended up with. That plus the company is struggling financially and subscriptions are mediocre to say the least.