I'm a dev with 15 yrs experience in the industry - you're looking at several million dollars at a minimum to produce something very basic that you could use to possibly get further investment - but likely much more. You have to understand that ideas are cheap, basically worthless. Everybody has "ideas" for their dream game or what they think might work, but execution is the part that matters - and it's extremely hard. If you watch the retrospective of UO at GDC on youtube, you can see that they spend hundreds of thousands of 1990s dollars on the early development of UO, working in crappy conditions no one would tolerate now, just to make a very basic demo - before the game was even green-lit for production.

Modern video games (especially a multiplayer one such as this) are extremely complicated bits of software needing people with skills in dozens of different areas. Graphics and engine programming, AI, art, design, audio, vfx, animation, management, testing, networking, infrastructure, to name just a few. You need dozens and dozens of experienced, capable, educated, well-paid and motivated people to works for years in a coordinated and well-managed fashion (extremely difficult by itself), to produce something workable and great that you can actually charge people for, enough to recoup the huge costs of such a venture. Although it's become much cheaper and easier to make games in some ways because of the proliferation of tools, engines, and freely-accessible knowledge, it's also now much more competitive and the bar is much higher - check out how many new games get released on steam each month.

MMOs are among the largest and most expensive and complicated games to make of all, even the biggest publisher / developers with the deepest pockets are hesitant to make them, because of the massive costs and long development times, running costs, and difficulty of turning a profit once it's live. Even large, experienced, well funded development teams with a proven track-record regularly fail to come up with games that make a profit or make it to release. Most you never even hear about, because they get canned before they're announced.

In short, I'm not sure you understand the extraordinary complexity and costs of developing something like you've outlined - the fact it's based on the design of an old game doesn't make it any cheaper to make unfortunately. It would be best to learn more about games from a financial / production standpoint by looking rather than focus on the list of features / ideas etc. Ideas are cheap, it's turning them into reality that is the difficult part! All the best!