I agree with Comic-Reader Lad about Great Darkness Saga.
Going into reading it now is kinda like watching Psycho now and knowing about the shower scene. (Back when Psycho came out, killing off the lead billed character was unheard of and made the shower scene all the more frightening.)
You can't go into it 'looking for Darkseid', because that wasn't how it was written to be read. Readers reading it back then didn't know it was Darkseid until he was revealed (unless they guessed and got it right).
And Levitz wrote Legion like a soap opera. There were usually at least three stories going on at any time, with even more future stories being setup with foreshadowing.
So just reading a few issues is kinda like sampling the first half of the week of a soap opera. It's just the tip of the iceberg.