The ability to edit any post is one of the major features of the Stack Exchange system, disabling it would make the site much worse. There is virtually no chance at all that SE would disable editing entirely.
But even though the ability to edit is very useful in general, there are certain types of edits that have more drawbacks than advantages. Every edit adds some overhead as it bumps the question to the frontpage for review. A high frequency of edits can drown out the actual new content on the frontpage, in such a case even if the edits themselves are good, the effect of all the edits at once in a short time is negative as it makes the frontpage useless for a while.
While a question is still new and on the frontpage, there is no disadvantage to bumping it for even a minor edit. Though one should always try to fix everything about a post, and not fix a typo while leaving other large errors unfixed.
For old questions the situation changes a bit. Significant edits are always welcome, but there is some disagreement about minor fixes. Personally I still think that fixing typos and grammar mistakes is worth it for old questions, with the restriction that I would not go and hunt for this kind of stuff to fix, and that I would be especially careful to try and fix every problem in that post to avoid further, unnecessary bumps.
Closed questions that are likely to be deleted anyway should not be edited at all. Unless you make an edit that would fix the question and make it fit for reopening, one should not edit closed questions at all.
Radical edits are generally discouraged. If you disagree strongly with an answer, just post another answer yourself and downvote (or even flag/vote to delete) the other answer. The exception are questions that would be closed if they stay unedited. Drastic edits to make a question follow the site rules is generally acceptable.