As much as I would love to see anything or anyone challenge the monopoly Paradox has, this seems overly ambitious and the intended time span honestly makes me question the overall vision they have.
Yes, they should have made a shorter timeframe if they wanted a game that is in anyway historical at all and not just another map painter, even less connected with any reality than Paradox games are. They call it "simulation" but you can't make one set of mechanics that makes sense for all the history (or even from late medieval to modern) - unless you want something
very generic. Basically a more complex Civilization. There is no third, realistic, option. Well, in theory there is one: you can try to make a game so big and so complex that it will never get done. They probably will attempt to make it and fail. Or end with the generic, boring option. At least Paradox gets one thing right - they have several games with different mechanics to portray the history at least somewhat sensibly. Imagine a game made of CK+EU+Vicky+HoI using one set of mechanics. Not a good image.