Originally Posted by grysqrl
The way it usually works, in my experience, is trial and error. You can see your rolls and know which ones hit and which ones didn't. So you try a few different things, prodding your enemy's defenses, to figure out "how difficult is this guy to hit?" and then adjust your strategy based on what you learn. If you make a bunch of attacks that feel good (high rolls) and you're still missing, you adjust your strategy.
That's is very un-fun. And then spend way too much time replaying encounter again and again, casting various debuffs and dispells hoping that you will figure out what you are supposed to do.

I can only see it work, if game had ways of communicated why and by how much you missed without showing actual numbers (as I would imagine a good DM would do when describing the action).