Fantasy worlds can be like ours in outlook and attitude, they just come with "added magic" but given we manipulate and abuse power, that too can happen in fiction. The magic can be abused in itself in order to control others but it can also be a complication for those who want to right wrongs in that fantasy world. Do they use magic to achieve their objectives? If so, how can they overcome those who are equally magically powerful but who do not share those objectives? What do they do about those who fear magic and abuse its practitioners? Can they themselves be tempted to go to the "dark side" and abuse their own powers?
So many stories can come out of answering those questions and I love reading those tales where characters struggle to do what is right but get there eventually. (The Lord of the Rings for me is the example here. I love the way Frodo gets tired and wants to give it all up, you just would, but keeps going and keeps going and so on. Sam has a crucial role to play in helping here. I have a very soft spot for really good sidekick characters too).
Equally a fantasy world can be totally different from ours and it can be huge fun to build your own world and set your own rules. (They've got to work though! Also magic should never be the answer to everything otherwise you will have no conflict and without that there is no story).
What every fantasy world should have then are characters that make you care about them to keep reading their stories, a world you can picture whether it is like our own or not, a classic good -v- evil theme (it has to be there somewhere, almost all stories regardless of genre boil down to this eventually) and a decent ending. (Nobody said it had to be happy. Have another look at the classic fairytales. The Little Match Girl has a tragic ending and so has Hans Christen Andersen's The Little Mermaid. Disney simply could not have filmed that story the way he wrote it. Why? Because it is violent, grim and as for the ending... well go on and read it. Suitable for kids at bedtime? Yes, if you want to give them nightmares! But HCA is to be applauded for writing true to his characters and not flinching from an ending which is the logical outcome of all he has prepared beforehand. Ultimately that is the duty of every fiction writer - be true to your characters).