@SenseiMatty
I have not read the 7 pages here, I am cooking and the dog needs a walk.

So, I am sorry if the following was said perhaps before already.
I've been in this business for decades, dealing with developing teams, the market, the management, balancing expectations and resources.
From my own booklet, I would never.... and that is an absolute, written in stone.... make a statement about a release date that far into the future like they do. I think this is not advisable, for many good and real reasons, it can only go wrong from where I am standing.
That aside, they use their own engine afaik called cobra, and this initself poses a challenge because you need specialist programmers at home in this environment. Hire a C guy/gal and he/she will be able to get into it, but it takes, does it not!
To speculate on feasibility concerning features is looking into a crystal ball. They will have to deal with many roadblocks until their announced Q4/20 release hope, and release they will something probably, but what it will be...<shrugs>.
Honestly, I doubt that 100 fulltime people work exclusively on EDH that would be some serious manpower, but say that would be the case, I would estimate that only a fraction of the 100 are coding, the majority will be artworks, graphics, ray tracing, mission design, BGS, sound design etc. etc. I would not be astonished if the hard core coding team is something about 20 people if at all, but this too is pure speculation of course. So they get the stuff on the table and have to implement the ideas and hopes of the rest of the team, you can't pay them enough to be honest, because that is exactly where all the pressure cumulates.
That being said, I do not wish to leave without saying that EDH already is one Heck of a game, unusual, not your average 0815 shooter, astonishngly deep game aspects that I can see playing for years to come, and at the end, I wouold think and hope they get even better at what they do...
just my 0,0000021 ton of painite.