When I homebrew it is to fulfil a fantasy not yet supported in the game. Such as a necromantic bard. My way of thinking when it comes to roleplaying games is that the class you play should reinforce the character the player wants to play instead of having the class smother it. I want to avoid the scenario where a player wants to do something with their character and finding out that they can't due to mechanical constraints.

This is the reason I have always disliked rules such as "a bard as equal amount of inspiration as they have charisma modifier", this forces the bard to go charisma to be able to use their class. Yes you will never see a bard that won't build charisma, as that is integral to the rest of their build, which fair enough. I still dislike it due to it's restrictive nature. Honestly I like the Idea of a bard that is far more into the research and historical aspects of the bard role. Mabey that will be my next character.