fantasy - Powers with unknown limits vs ones full of rules, limits and reasons?

I'm in a dilemma: I don't want my characters to have flawless, limitless and bad-consequence-less powers, but I also don't want to have my creativity limited by such rules and limits.

In my case, it's not a book, but a multimedia work, i.e. such powers are visible, with flashy effects and all, instead of just imaginable, so the possibilities are different from books.

I find it awesome when I see a work where the creator has the freedom to make the character use a new power out of nowhere, usually a character whose powers are not much explained (or even well explained, but in an unexplainable/incoherent way they manage to do that) and most of the public just don't care about how the character found out that he could do that, or that doing movement X would result in such new power, or why it happened, no, they just like it, because it's cool, if it's cool, screw logic, it's cool!

I want to have creative freedom to create the powers, but I don't want to keep the questions above unanswered. However, the more I explain the whys and hows, the less freedom I have, and the more I try to fix things up, the more incoherence is created.

Now how to resolve this dilemma? Do I keep all the rules and sacrifice "coolness" for the sake of coherence/realism, or do I surrender to the "Rule of Cool"?

Answer

I am in favor of rules and coherence. However, also remember that you do not have to show all your work.

Just because you as the writer/creator know how magic/powers work doesn't mean you have to tell readers. Mercedes Lackey has a widely developed magical universe and only once, sort of in passing, mentioned where magic "comes from" or how people can access it. The rest of the time it just is. Poeople are inborn mages or they aren't.

One of the benefits of rules is that it forces you to think about consequences. What happens when you break the rules? What happens when your character runs up against a limitation of powers?

In David and Leigh Eddings' Belgariad/Malloreon series, sorcery is essentially limited to the Will and the Word: if you want something badly enough and say it, it will happen. But: You cannot unmake something with sorcery. "Be Not" is one of the few checks on ultimate power. The backlash is that the sorcerer/ess explodes. Why? "The universe gets offended." No more than that. Where does magic come from? Dunno. It just appears if you will it hard enough. Will is enough of a barrier to overcome that not everyone is a sorcerer.

Having a powerful character thwarted by "Captain, ye cannae change the laws of (magical) physics" creates conflict, and conflict is how your story becomes interesting. Two all-powerful whatevers bashing away at each other is a flashy spectacle on screen, but it becomes boring and unbelievable after a while (and faster so on the page).

Embrace rules and restrictions. They will force you to think more creatively, and therefore increase the conflict your characters have to overcome.