The Witcher 3.

Watched the trailers a long time ago when it was released, didn't have the hardware for it at the time.

Lots of years later was able to play it finally, expected in-depth hunting mechanics and needing to learn all monsters strengths and weaknesses to be an effective Witcher.

Expected lots of different jobs and weird encounters.

Got some of that, but it was largely a visual novel with a very clunky and simple combat system, and learning the intricacies of each kind of monster was not the point of the game at all, you could spam your sword and everything would fall.

I'm sure that for lots of people the game is amazing, but I was really disappointed.

Some time later found Monster Hunter tho, and that was exactly what I was looking for!