I've given 10 estimates on when the game would be out in the past 4 months. All of them were wrong, those waiting have been gracious enough to be patient but It's still at 99% (after 3 weeks) and still not done. I anticipate being done soon, but the reality is things take as long as they do.
I'm not really trying to play devil's advocate here, just sharing reality of what goes on behind the scenes. I might be a single person, but his project is also 8 years (and a ton more content ) larger than my own.
Even with a group, it's really not inconceivable that this update would take 2 years to develop. Professional games do that (and longer) often. For context, the last time I played SS it took me about 3-4 RL days (nonstop) to play and about 120 something hours.
Comparatively speaking, RPG games only offer that kind of replay value and only through new game plus. We're talking all fresh content. Have you considered that DC really did give you an estimate that he thought was feasible at the outset (aka 1 year?). Maybe he just didn't realize it would take twice as long - but in the end, would that really appease you? It seems nothing short of the game will at this point.