To be a worthy game in the Elite saga it has to be ambitious. These are games that break the mould. Each one has done things never before (or since for that matter) seen in gaming history.
Certainly this one is ambitious. But no, it is definitely not too ambitious.
The thing with this game is that it looks crazy ambitious compared to contemporary games. But in seen in it's own context, everything it's trying to do is well defined and achievable with the way Elite games work.
Most games focus on the details of the finished product, where as Elite games focus on the details of the component parts.
Say I find a rare mineral in the rings of a gas giant, and get attacked by smugglers. That's because the game has gas giants, minerals, and smugglers. In most games it would be because someone took time to create that specific scenario. There would be no other way that could go than the way it was written - whereas in Elite, every different component they add multiplies the possibilities of what's already in the game. They don't have to spend time inventing complexity or contrived mechanics to keep known scenarios challenging - or delegate all unpredictability to multiplayer - because everything that happens is a one-off.
Each gameplay component spec in the design discussion forum is sophisticated, but all are very clearly doable. None of them alone would make for an amazing game, but put together they form endless possibilities. Large scale multiplayer, and getting out of your ship are I think the two big new things that have yet to be proven. The latter, mainly what they do in populated areas as I have no doubt that they can implement that in ships interiors and in the wilderness. But they have been smart with their approach - they're testing the multiplayer systems right now before a lot of the other stuff is opened up - and the out of ship stuff they have devoted an expansion to.
When you look at how they've broken it down, it's very much something they can pull off. It's only when you think about how it will all look as a finished product that it seems impossible. Which is development, done right.