How much do we actually know of the game? Not all that much. No intelligence, no diplomacy, no detailed information about land combat, no explanation of how the battleplanner will work, most of the technology tree is still unknown, supplies, no information of modding capabilities, no information of any other country than Germany, no information on factions, no information about how stockpiling goods will work(except that we won't have as large stockpiles as in HoI3) and no information about economics.
We're straying from the topic a little here, but compared with the vast majority of titles four months out from release, we actually know quite a lot. That's the point I'm making, not that we know everything already. As an example, I'm looking forward to the Witcher 3 as well (due out a month before HoI, and with a team that probably has more than one person dedicated to marketing just that one game), and we know a decent amount more about HoI4 (put together with a team that could, in all probability, be smaller than Witcher 3's marketing team) than we do about Witcher 3. Given that we find this out from people putting in to support their fans in their spare time, I think there's a decent argument for being appreciative. I've seen a lot of developers in my time, and PDS/PI don't get everything right (no one does) and some things they may get right won't please everyone, but they've both improved in leaps and bounds over the years, and treat their fans/customers pretty damn well and seem to do it with the right attitude (and a so-sharp-you-could-shave-with-it sense of humour