Over the past few days I've been going through some of my old Hobbit movie answers updating them where appropriate for new info contained in the third movie. This mostly relates to "why did..." speculative-type questions about movie-canon info that hadn't yet been available at the time the question was asked. In all cases I've let the original answer stand but have just added supplementary paragraphs.
Anyway, while there's value in having these bumped (so that the update is more easily visible) on a couple of occasions I've made a trivial edit: for example in my answer to Does Thorin have the last Dwarf ring? I've recently made an edit to correct a typo - an "s" to an "r" - and such an edit hardly merits bumping.
There doesn't appear to be an "opt-out" option for bumping. Now, I can understand at least one reason why: we definitely don't want a batch of destructive editing going on without anyone becoming aware of it. But in the case of high-rep users (or users sufficiently trusted by virtue of having, say, a relevant Silver tag badge (which I should note I don't have, but am close to) or something) such an opt-out would definitely be useful.
It would at the very least enable us to do useful community work such as spelling corrections, grammar corrections, retagging, and other housekeeping/fix-up without swamping the front page with bumped questions that are of minimal or no interest to anyone else.