Re: So did Worf's Change of Heart cost him command of the Enterprise?
Worf has made a few questionable decisions in his career, such as firing on an unidentified ship as it decloaked, sacrificing a key intelligence asset for the life of his wife, giving up his post as UFP Ambassador to the Klingon Empire for some reason, all of which would go against him.
I don't think giving up his diplomatic position would have affected him in any way unless it happened due to disciplinary problems. People change careers all the time for reasons that aren't necessarily negative. Worf was more likely to face scrutiny for the other incidents you've mentioned, as well as his killing Duras against Picard's orders.
"He clapped his captain—his friend—on the shoulder. Yes, this man was very much like James Kirk, in all the ways that mattered." --Christopher L. Bennett-- Star Trek: Mere Anarachy, The Darkness Drops Again