That isn't much at all to compare. Most of that has nothing to do with what the shows are even about. What does Netflix have to do with anything? A lot of things are cult classics and share nothing else (like horror films and comedies). The time lapse was approached so differently in both shows. The ensemble cast is all they really have in common and the fact that they are comedies, but that means next to nothing because humor is so subjective and there are an immense amount of genres. WHAS is easy to categorize as parody and, well I don't really know how to describe AD. It's a lot of different styles of comedy. I guess just comedy works.
But the approach to season 4 and FDoC is very different. S4 was an anthology show were everything links together and overlaps and it's continuing the story 7 years later with a very tight continuity. I don't think there is anything else like that. FDoC is serialized, a prequel, and where continuity and logic don't matter. FDoC has all the freedom in the world to do whatever. Continuity is there to strictly make a joke about. AD has to show what happened over 7 years worth of time and set up a story to bring all the characters back together to the present.
As far as season 4 forgetting what made the show great. That's something anyone could say because it's not really something that can be proven. It's just an opinion. Someone could say the same about FDoC. All you have to do to say that is you did not find the FDoC funny because they are here to make you laugh. If they fail at that, they they forgot what made them great. Nonetheless, AD S4 still used very tight continuity, an ensemble cast, all different styles of humor from vulgar to subtle, densely packed episodes with jokes that pay off way down the line or way early in the line on a rewatch. It has all the hallmarks of previous seasons, but it was forced into an anthology series by the circumstances of all the years passed. Everyone ranted about the ensemble not interacting enough, but they were rarely ever all together in the first 3 seasons.
And another thing I'll bring up about AD, is every season, when it aired, was criticized by the fanbase as being worse than the last. I watched every season when it aired and I can remember fans saying season 2 lost what made season 1 great, and Season 3 was weak and it was good the show was cancelled.
It will be interesting to see what the re-cut Season 4 is like, but I don't imagine it'll change anyone's mind.
Anyway, I love Wet Hot American Summer and Arrested Development. Both of them getting a longer life makes me happy. I'll be there for whatever comes next.