I'm still not convinced that he was the cause of OMWF. I thought it was Dawn on my first watch and even on the second watch it was still debatable IMO. It just seems like poor writing to pin it on Xander.But S6 Xander got somebody killed with his actions in 'OMWF'. That's way worse than anything he did/tried to do during the high school years.
Also grown-up Xander can still be a judgmental grade A jerk when he wants. I agree that's he's better in many ways to older Buffy or Willow but he's also worse than his high school self.
It's just a curious observation, not a criticism.
And of course Xander still did some jerky things, but he definitely improved and this is coming from someone who is not even close to being a Xander fan.