It's absolutely necessary. You can see the beginning stages of writing pratfalls nestled within AtLA that would go on to become the bane of the Legend of Korra.
Beside all of that, I love both of these series for different reasons. Sure, it would be nice if the Legend of Korra had characters as well made as AtLA. But there are things in Korra that I like much better than in AtLA. I'm glad I can enjoy both.
Yeah, I will say...while I think ATLA is better than Korra in almost every way, there are things that Korra certainly did better.
I always went into Korra with the mind set that it would be its own thing. The writers...kept trying to connect both series (lol which made it difficult). But I still tried to view it as its own separate thing.
Honestly, most of my issues with Korra while I do think, they are problems carried over from ATLA, were kind of issues I felt were in the context of Korra. Like, I didn't need Korra to be as good as ATLA. I think, we can have those discussions of how one series did something better than the other. Or, try to figure out why we liked one series more than the other.
But Korra was not worse for not being as good, or being ATLA. I think, whatever issues it had, were self contained issues that fall back on Bryke and the writing. There were always going to be people that didn't like Korra for not living up to ATLA, or not being ATLA. And that's fine. You were never going to please those people.
However, Korra as its own thing, then became accountable to itself. And that's where I think some of these issues within Korra are valid to point out. Like, they are issues that weren't there simply because of the pressures of living up to ATLA. They were just issues in general within what they were trying to do with Korra as its own thing.
I remember when Book 1 came out, a lot of people had a chip on their shoulder. They kept wanting the show to be ATLA. And I totally just accepted Korra as its own thing. And I fell in love with it, as its own thing. I still think Book 1 had writing issues, but I don't think it was a result of living up to anything. They were just general, basic writing issues.