The crossovers have been entertaining, I'll give them that, but they've also been very cluttered; when you've got to write for so many central (and supporting) characters, there simply isn't enough time to make anyone truly stand out, and there's countless character interactions that were missed because there just wasn't time for them.
I think they've also suffered somewhat by each episode having a different writer (whereas this new one is being wrote by the same person?) The longest crossover we've had to date would have been Crisis on Earth X storyline, and that was what, 130-140minutes worth of screen time? Infinity War probably had less characters that Crisis on Earth X, and even Infinity War (which had a longer screen time) lacked on character development (understandably so, there was a lot to cover).
I just think, personally, that there could be a stronger focus on smaller crossovers; two parters, either between Kara & Barry, or Barry & Ollie, or even Ollie & Kara (somehow?); Legends can practically fit in anywhere on Earth-1, and so can interact with Barry and/or a future version of Ollie on a whim (they already have with Ollie IIRC).
Focus on the story, not on throwing as many people together as possible for the same of viewers. I am optimistic about Elseworld, cause there's no Legends in it, but I remain cautiously sceptical; Stephen and Grant (at least) are playing three different characters per.