I'll let a team member give you the official agenda for the tool's development. I do know they are working on the grammar, and several incremental feature additions. As regards the bug list and stability, my assumption is that most bugs are accounted for - even if they were not noted as fixed (because the newer versions did not have the same issues). While still in CTP, I find it more stable than some released applications. Also, some issues with nORMa are actually Visual Studio and DSL Tools issues.
Your concerns about using a CTP application for an important project are legitimate. However, given the nature of the tool (what it does), I think you could use it as part of a set of tools (verifying the results with something you feel is more stable).
You can certainly use the ORM methodology to analyze the UofD for your project. The first steps there will be of value to you, no matter which tool(s) you opt to use. I'd try to model it with nORMa, and see how far you can get. Matt, and the others are helpful resources if you reach an impasse; and would want to know about the stumbling block in any case.
What I don't think you can assume is that the current version will provide a turn-key solution, giving you a complete physical implementation in your DBMS. It should get you close (likely closer than any other approach). You also can't tell the stakeholders that using the tool guarantees anything - but what does? You ought to end up with a self documenting conceptual model of your application domain, and a reasonably close DDL script.
You provided a number of tables estimate. I'll accept that you know that by experience. My approach is that the tool will tell me how many tables, and more importantly their structure connections. Yes, you can estimate the number of tables by looking a a list of entity terms in the UofD; but how do you guess at the tables for the relations? Don't be surprised if mapping the completed conceptual model gives you a different number.
I'm curious, what methods/tools would you use for this project if ORM2 and the nORMa tool were not available? Most business projects have restrictions on disclosure. If this doesn't apply here, feel free to pass along project details. Use your good judgment, and good luck in any case,