Fallout 4 can be considered a massive evolution in the series. Its focus on moment-to-moment gameplay, scavenging and some engaging shooting mechanics may be controversial in the eyes of some, but no one can argue it doesn't create an exhilarating experience. That said, a lot of people criticise the game for simply not being "Fallout-y" enough.
It's a valid criticism, as the RPG mechanics of previous games have obviously been toned back, but a lot of previous mechanics also had the axe. In the name of streamlining, a lot of minute and somewhat necessary mechanics to the Fallout experience were lacking in Fallout 4.
Some of those mechanics are understandable considering the direction that the game was going, but a lot of them are genuinely baffling, as they would have actively improved the game overall.
Going forward there's no point belabouring what could have been. Instead, let's focus on what could be.
With Fallout 76 around the corner, Bethesda could create an incredible experience if they simply revisited their roots, reviving some discarded ideas and bringing them into their new vision for the series.