Ultima Online's second expansion in 2000 (yes, 2000) came a copy of the world, a facet called Trammel where non-consensual PvP was forbidden. Ever since, the current and former UO community has debated whether this was a brilliant or terrible move. Now we have the word from former Executive Producer Gordon Walton, who discussed Trammel on the Crowfall forums.
"I regret some (but not all) of the outcome," Walton began, going on to explain that the rampant PvP was driving away over 70% of new players to UO. The creation of Trammel doubled the playerbase, but he said that it disenfranchised the hardcore PvPers who now had to prey on each other instead of PvEers.
"I also learned from my UO experience that it's really hard to change a brand," he wrote. "Inherent in the UO brand was the fact it was a gritty, hard core world of danger. We were not successful in bringing back the (literally) hundreds of thousands of players who had quit due to the unbridled PvP in the world (~5% of former customers came back to try the new UO, but very few of them stayed). We discovered that people didn't just quit UO, they divorced it in a very emotional way. But we did keep more of the new players that came in by a large margin, significantly more than than the PvP players we lost."