I think it's worth chiming in to say that while you may be attached to your intellectual property, you lost a lot of points from many of us for shutting the game down without releasing it. That's fine, but that does mean that you have a proven track record of yanking it out from under players. I doubt you care about having players judging by your initial post, but unless your goals have changed you're building something graphical and from which blind people will be excluded in future. Whether or not someone continues developing it, I'd suggest that you commit to open sourcing it if you take it down again. No one sighted is going to care about your moo, not enough that it could even slightly detract from the players you'd get with a non-mud project, so it's worth considering that you might as well let blind people continue running the thing that ultimately only blind people are going to be interested in in the long run.
Kind of nevermind if your motivations changed and you're actually going to keep it as a mud or make something accessible, but even so: lots of great games that we'd have kept running died off because their authors walked away and wouldn't release anything because of the "it's my property, grr" mindset, even though they knew they were done with it. It's always sad, in the sense that there's very little quality blind accessible games out there, and also in the sense that even though it would be of immense value to the blind community to be able to preserve the few that did something different we can't without collaboration from the devs. Dark Legacy, Project Bob, I'm looking at you. Though those games were in the previous generation of young blind gamers, so I'm probably one of a very small number of people to remember them.
For my part, I might one day play again, but "the game is disappearing, sorry, there goes all your progress" turns me off.
As for the quality of open source moo? Open source moo can't work because moo can't work at scale, and was originally designed for social chatrooms plus a bit, not full-on combat-based muds. The primary advantage of open sourcing in this context isn't giving people quality code, it's providing a plan for the longevity of the game. Blind people are a captive mud audience: we want the good ones for at least the net 10 years, and have become the majority playerbase or damned close to it in the last 5. There might be an audio MMO of some quality eventually but I think I'm the only one contemplating writing one who has the skill to even try currently, and if that's going to exist it certainly won't before 2025 simply due to the lead time of that kind of project. Maybe someone is silently working on it and hasn't said a word and is going to come out of the woodwork tomorrow and be all "blind World of Warcraft". But I doubt it.
Anyway, food for thought. Take it or leave it as you choose.