There are quite a few loose ends. Like I'd like to see some more Korrasami and I'd definitely like to see more Kuvira. I also find it odd that we saw nothing of the 'modern' Fire Nation as it was such a super important place in Avatar.

I haven't seen season 4 yet, so I can't judge yet. But it wouldn't surprise me because despite this show being really good, it's also really flawed.

^^I completely agree.

Yeah, like zanhar said, where was the firenation?

Yeah..... there were so many left open plots, there was a serious need for some more character development, and the ending really did fall flat.

^^ It just peeved me so much.

Even though they've explained some things from the first series in greater depth (like the spirit world), I wasn't satisfied on the ending. There was a lot of characters who can improve, and the ending seems like it was rushed.

The fire nation was not really 'involved' with anything happening in the present anywhere in the entire series. The only time that the fire nation was included was when they had the republic meeting, when Fire Lord Izumi refused to help strike against Kuvira. The solid fact that the fire nation was not able to get more screen time makes me scream inside like a banshee.

^