the first crisis is just an awful comic all around
the thing is, i think they were "fixing" something back in the 80s that, to me, didn't need to be fixed
i've been reading comics off and on since i was around six years old, and i never, not once, found the concept of multiple earths hard to grasp
mostly because in the days of newsstand distribution there used to be footnotes and asides in the captions to catch you up to speed on things you might have missed, a practice that seems to be regarded as taboo nowadays - also because, for the most part, they tended to keep the "earths" separate and distinct
say what you want about jim shooter, but he once said that creators should always keep in mind that every comic has the potential to be someone's first comic, and they should always strive to make every issue as accessible as possible
if, back in 1985, they really thought the multiple earths concept was intimidating to new readers, and had become too convoluted, then they should have just stopped using it instead of trying to "fix" it with a story ten times as incomprehensible and convoluted - it was a concept that was destined for failure, because they've been trying to explain all the "fixes" for decades, and every explanation just muddies the water further