some spoilers ahead
I definitely have some criticisms about the first season. For example, some of the child acting performances weren't that great and I have some issues with how they handled some of the main plot points (combining the Jet, Northern Air Temple, and Omashu plotlines together). However, it's visually stunning, the soundtrack is great, and Zuko and Iroh are done incredibly well. Their characters are well developed and their relationship is fleshed out. Big props to both actors. I think Suki was also written very well, and her actress was perfect. Always love to see some Kiyoshi badassery too. Overall, I have a positive outlook. I would probably rate it 7/10, but I'll round up to 4/5 for Google. It's far better than the dumpster fire that is the 2010 film, so I see it as an absolute win.
I hope we get to see a lot more of the main trio bonding if/when we get the next season. IMO even in the original, the first season is the weakest, so I look forward to the next two seasons of the adaptation to hopefully be even better.