Eh, I find that English lit is packed full of content that simply has to be engaged with in order to do well. So no, I would say that doing that is not enough, to be brutally honest.
I do both Biology and English literature, and I did better in Biology - even though I revised more for English Lit. (Granted, perhaps only a week more) Biology is hugely content based, and therefore most of the time it is easier, as long as you revise properly. On the other hand, English demands flair, creativity and more than just a few flimsy arguments - all of which is hard to construct under time pressure.
Not entirely sure why you think English lit is a subject lacking in content, when the best students know their books inside out and back to front with detailed analysis and critique.
Actually, you sound a lot like me during my first year - I thought I would get an A easily in English Lit because teachers acknowledged I was talented in English and could most certainly get good grades, so I just stopped trying. Unfortunately, that doesn't work. English Lit requires a lot of effort, I would argue, and a lot of practice - perhaps even on par with Maths? (I do that as well by the way)