the only people who really miss pre-trammel UO are the killers
...And the cops... and the people who want something more out of an MMO other than endless grinding and football matches (organized pvp).
There was something to be said for actually entering a world which contained some vague simulation of real danger and some consequence for failure. It's true that pre-Trammel UO was extremely unfriendly at the entrance to the learning curve, but someone who was actually interested in a challenge could thrive in UO either despite or because of the constant predation. It drove the in-game economy for the "sheep" as you put it. It made a niche for those people who kept the griefers under control. It allowed for interesting social constructions like bounties (although the in-game bounty system was useless, far better when dealt with informally by players).
More to the point, it made you value what you had more and be less interested in minmaxing your equipment when it could go away at any time. The things you had were ones you worked hard to get and fought hard to keep. It made the uncontrolled and unguarded (by players or NPC) areas more lively. Contrast the Darkness Falls from Dark Age of Camelot to any other dungeon in the game and you'll see the one with unregulated PVP that you had to fight hard to keep out of the hands of your enemies was more populated.
Finally, there are other forms of griefing than just killing people and not letting them get their stuff. Annoyance tactics and social griefing is far more disruptive than PVP ever was. UO had a rather expedient way of dealing with that - if somebody was really annoying you and the people around you, you cut their head off and sold it at the bank on a vendor.
I played for 2-3 years as a "local militiaman" for the largest player-run city in UO (at the time) during my days off from work (I worked a 14 hour graveyard shift 4 days a week). It was considerably more personally rewarding than any subsequent PVP or PVM-based game I've yet seen.