Exactly. I'm not implying he would be able to beat Eredin or Imlerith in combat, but he would give any of them a hard time for sure. The thing is in books Ciri managed to beat Eredin with luck and escape because he underestimated her, I don't think he would repeat the same mistake with Vesimir. If he took him as a worthy opponent he would eventually obliterate him but I believe uncle Vesimir would put one hell of a fight - same goes for Imlerith. I have to say I liked the way they handled his death in the game. I appreciated it and cried a lot. Imo it was a very noble and meaningful way for him to die,
saving Cirilla of Vengerberg.
My problem is that he didn't actually save her. I mean, if she had legitimately gotten rekt and Vesemir charged in, wounded people, and actually bought time for Ciri to recover or for Geralt and the others to not be frozen, that would have been him saving her. But instead he does a lot of annoying Eredin and Imlerith, while shouting at the bizarrely useless and passive Ciri to run. Then he decides to annoy himself to death, at which point Ciri stops being useless and saves herself and everyone else through a sudden and unexplained powerup, that could apparently only be triggered AFTER he dies. His effort was noble, his performance sucked, but ultimately, his death was meaningless because it only served to remind Ciri that oh, yeah, she can totally take care of this after all. It's such a tired trope, and cheap drama to end a character that way. So many books, animes/tv shows do this and it drives me nuts.
"Stop killing my mentor right now, I mean it!"
"Haha, no. I kill your mentor"
"Oh you've really done it now! Guess I'll actually do something about it now that he's dead, lol"
Anyway, I don't know if Eredin would have been able to obliterate Vesemir in a serious fight. He's shown himself to be a skilled swordsman, but not exactly god tier. From the books Eredin came across as being less threatening than Bonhart. I feel like that fight could go either way.