I disliked civ6 due to the warmonger penalty. It seems like all the other civs will dislike you for hundreds of years for waging even a defensive war agressively.
That is fixed with the Gathering Storm expansion. Warmonger Penalties are replaced with Grievances, which each civ tracks individually against each other civ. So long as you have more Grievances against a given civ than they do against you, other civs do not care what you do. It makes fighting defensive/retributive wars much easier. I think it works pretty well overall.