I absolutely love it. All subjects are what you make them out to be, or more precisely, what you put in is what you get out.
The key thing is all human action is purposive (has a purpose) and governments aren't magical wizards.
You don't need to be good at certain subjects but a strong grasp of English and being able to churn out essay after essay after essay...is useful. Have fun with the essays though, even if you do end up with a U in one (the story behind that is when everyone else thought about the bog-standard fiscal/monetary policy, I thought about privatising the money supply. Got me a U, but my teacher told me it was the most exciting essay she'd read...weird.)
The key to any kind of Arts subject is to reads LOADS, get as many different point of view as possible. Its better to read 3 different points of view than to read 10 tomes all coming from the same angle.
And no, it isn't seen as a mickey mouse a-level. Altough it has been seriously dumbed down by AQA ready for 2009.