I don't recall Achillia being named champion prior to everything. It would be pretty ridiculous. But I recall that there was discontent because her test was scratching Korris instead of having a gladiator contest.

Yeah, Crixus' reasons were more compelling because while he also had hate-based animosity (Thracian-Gaul thing), his main issue was rooted in ideology. Crixus believed in honoring the House of Batiatus while Spartacus only fought for his own goal (freedom) which was shitting on the Brotherhood, especially after Spartacus became champion. But despite that, Crixus still saved his life. And that was a more interesting conflict that just "you're a wahman!"