Through discussion of differing opinions is where growth occurs. Growth can breed creativity, so I don’t think controvery (whatever is meant by that) really controls creativity. I would say creativity is stifled more by the buying trends of the American public. Well respected magazines about writers and literture, that used to be prominently featured in bookstores are relegated to a few copies way at the bottom of the shelves (if they are there at all.), and certainly many writers will not write and publish something they don’t feel will be commercially successful.
It's a pretty general question, and I think it really depends on the particular controversy. I do know that in literary studies, some of the in-fighting got pretty ugly. In the department at my University, there was a huge rift between the New Critics and the ism's scholars. So the newer, younger faculty really detested the old guard. In that case, it seriously impeded creativity because a number of the faculty members wouldn't even serve on the same committee for grad students. My dissertation advisor openly referred to some of her colleagues as "idiots." So...not much collaboration happening there. That, in turn, made it difficult for grad students to work outside of defined critical areas or approaches.
But, at some literary conferences, I have seen some lively and relatively friendly debate where all the participants left with new ideas. At other literary conferences, I've seen people shot down by the more famous scholars after giving their papers, essentially cutting off discussion. It really can go both ways and depends a lot on the personalities (and egos) of those involved.
While I agree with Akannan that additional definition of corruption is clearly needed, a simple answer to this i\lies in the fact that controversy is a key element of discourse. When there are clashes in beliefs and opinions, as long as the discussion does not become a personal attack, new ideas are often formed. This is the basis of solid argument (persuasion, not "fighting") - one side hold an opinion, the other side holds a divergent opinion. Through well supported debate, both sides may find themselves meeting on a different ground - a process known as finding common cause. When this occurs, new ideas are often generated and change or growth is the end result.
I think that more definition has to be given to the term "controversies." Certainly, the idea of writers and critics holding different positions on intellectual issues helps to enhance the discourse and create a more vibrant debate. Writers who are devout Marxists hold their own set of beliefs which clash with the classical Liberals. The Postmodernist thinkers' beliefs of the lack of totality come in direct opposition with the Platonists' transcendent beliefs. The idea of different thinkers and critics holding different and clashing belief systems help to enhance literary creativity because the reader/ thinker has to make choices between divergent belief systems. Perhaps, to a great extent, the thinker/ reader has to integrate aspect of each in their own paradigm, giving birth to a new value system and increasing the level of thought into the discourse. In my mind, this can only be a good thing.