I'm going to be real with you, I too played at launch, was even a BETA tester. The game was a lot of fun with the people you meet and the adventure was a lot of fun with friends. I then eventually left after completing the main quests and doing as much as I could.
After returning back for the Wastelanders update, I did as much as I could doing the events and even comitted myself to do the first of the Season when it released.
I reinstalled 76 a week ago to come back to the content from when I heard about Fallout Worlds. A private world where I could make the game more difficult made it challenging and fun. The problem is I'm alone and can't enjoy the game fully with random players. After trying to redo my progress in Adventure Mode, I eventually came to a point where I was just, in the best way to put it, bored. The prolongued fights with enemies due to the way 76's mechanics works just didn't fit for me personally.
I am a huge fan of the Fallout franchise, my steam profile says it all, but sadly every time I play 76, I feel generally unachieved in my goals and unacomplished.
That is just my opinion though, there is plenty of things to do for returning players and I think it's a ton of fun with friends. But, if you love the challenge rather than the grind, you will not find the game very interesting for long, I am sorry to say. Especially with limited game mechanics to original Fallout games, like the Fallout 1st Scrapbox.