I'm sure they could actually give us more concrete information since they must have been working on this for a year now, pretty sure they weren't working on much else last year. Lack of communication is the norm for UO though and they seem to enjoy keeping everything secret instead of creating some anticipation by giving regular progress reports, of course that assumes it is something worth looking forward to...
I really suspect that the prototype is there already. I think the task of initial tweaks and adds to it, are likely time consuming, in order to do a halfway decent job of presenting it possibly on TC1 or some other test version. Re-programming also is another possibility from the C or C# code to the awesome Python code. Thats a pretty high level language, totally different graphics engines and easier to document program units. Maybe just wishful thinking, but pretty massive task to reverse-engineer the initial code, reprogram it with a different model language, then tweak, and add the thousands of mini-adventures/encounters that make up UO, and then add more to make it sort of a new experience.
ALL of this is just my conjecture and guesswork, with no facts at all available so far.
Couple this with the fact that likely there are only 1.5 programmers involved, plus the level or criticism and toxicity they get from both the "uo board" and also here, not too hard to see why taking one year to give birth to it.
Also I know that a couple of high-school kids can set up a uo server on their computer tweak and launch a version of uo in a week or two from their basement computer etc. But they go no-one to answer to really. They cannot get fired by themselves etc. They really have not got much to lose either way. But UO is UO, lots of shards and players, and, they do have a boss company that must be kept happy for the most part. They likely have their own in-company agreements, contracts and meetings they must keep up with. They are likely trying to produce some quality product and test before launching. They must try to avoid negative reviews and negative press, in order to attract new players.
The idea of a re-initializable shard is not unheard of also. There are some other much older MMO's there that have done it, also lasting one year, only at the end of the year there is complete wipe of everything, with NO carry over to regular shards of anything at all. Yet people played it to my surprise, even though that new shard was really tougher, and everyone know ahead of time the shard would be wiped.
I would vote to just be patient and hold our undies on and wait a little more.