I genuinely can't remember if he even had a speaking line in that flashback. They did Sokka sooooo dirty.
I know there's a lot of Korra enjoyers out there so I'll admit there must be some appeal to it but their treatment of the original cast is near the top of my list of reasons I hated it.
I think he has one or two, but yeah basically just completely ignores him.
That's fair, it's hard for a spin off series to capture the magic when a lot of the love comes from character chemistry. I personally grew up with Avatar on Nick and still found Korra to be enjoyable, but I didn't have as much of an attachment to ATLA as some people so I didn't really feel like it was missing that special something.
I like the TLOK cast, minor characters included. The only thing that never sat well with me was the rushed Asami/Korra romance that wasn't even really hinted at previously as more than a friendship, unless you consider her responding to letters as a specifically romantic situation. Obviously it would be difficult to get away with showing an openly bi/lesbian romance in a nickelodeon cartoon but it felt like they were just trying to imply it for tokenism instead of committing or just not having Korra end up with someone at all.
"Yeah, after the fire lord is defeated and everything returns to normal, Toph admits to Sokka that she's wanted him ever since the bull moose event in book 3."