There's too many of them? I put it down to that. I like these crossovers, but I'd prefer if they were more doubles rather than trying to cover everyone; in the sense that I'd rather a crossover between Arrow & Flash, and then another one between Supergirl and Flash and maybe a third (next year) between Arrow & Batwoman.
As good as Elseworld was, and as good as (I expect) Crisis will be, if the writers have too many characters to write for, everything is just jumbled. Crisis on Earth X was an example of them; too many characters that many other characters were thrown on the sidelines, the same goes for that other story involving the Dominators.
The crossovers have gotten better as they've gone on, but I think, with the latest one, that's in part because the Legends weren't there.