The name for the project does not determine that the eventual project will be found at "http://ultimate.wiktionary.org". There are reasons for it and, there are reasons against it. It is cheap to name it like this as the domain wiktionary is already owned by the Wikimedia Foundation. The second reason is that a fair number of people already know this name and finally it does link the old with the new. A big argument against is the use of this "ultimate" label. The functionality of the software will grow but at first there will not be much that deserves this accolade.
Now there is this opportunity; what name to pick and, what arguments to use
Wiktionary2 is another great name it. It also gives a great link to the current Wiktionaries and it symbolises well the big technological step that it represents. One thing that is problematic that some people suggested that it could be seen as a version number; this would mean that the future might bring us a "http://wiktionary3.org". This is not a sensible way of doing things as you do not want to reflect version numbers in your domain name.
I hope that people will like these suggestions, and there is room for many more.