I thought we saw Nero somewhere... maybe during the sinestro corps war as a way to wipe him off the board or something... Some time when Ion went to the daxamite… I'm not sure now. I liked how he was flat out insane as opposed to Sinestro's facist 'order above all' concept. it was like his own joker or Carnage that you just couldn't predict what would happen next.
And yes... a lot of Kyle's charm was the fact that he was NOT associated with the Corps. he was NOT trained... he was Not 'worthy' and he didn't have years of experience and the 'book of oa' to fall back on. He was just forging his own way, making his own mistakes as best he could... and yeah, Sinestro wouldn't have any respect for him at all. He isn't even worthy hating in Sinestro's eyes. He hated the Guardians. He hated Hal Jordan for constantly being the guardian's champions.. and he hated the GLcorp for being the Guardian's puppets.... but Kyle? He really wasn't any of that. He didn't even wear that hated uniform or wear that symbol.... He'd really have as much animosity toward Alan Scott or Jade as he would Kyle... they were just... Beneath him.