English isn't about finding a formula to write essays, it's about developing a piece which is creative and unique in its approach.
In all respect, I disagree. I think text response is the only section that requires genuine talent to do well at, as there is no real memorisation or formula that works well for most students. Personally, I found LA to be formulaic and Context to be much easier if you have a few pieces cemented in your head (the ideas, themes, quotes, or even the whole piece). And I know a fair few people who would agree with me there.
Language analysis isn't formulaic, it's logical.
If your formula is inherently logical (ie. you've actually put a bit of thought into how it can adapt to wide range of articles/blogs/whatever), then you should be fine.
I was taught a formulaic approach during tutoring, and pretty much everyone was fairly comfortable with LA after giving it a go on a variety of sources.
Although, as I sad before on one of the threads, it's up to you. Some people enjoy writing something different every time they approach a LA, but in all honesty, those students are those who have a fair bit of natural talent in English as it is. For a student like me, who before yr12 was a fairly average English student, I found that using things like a formulaic approach really aided my understanding of the task and also my resultant mark.