Community Wiki isn't meant to save questions that turned out of hand, let's get back to the roots...
Is that question constructive?
There is no point in turning something in a community wiki if it's not constructive in the first place.
What keyboard shortcuts provide the biggest productivity boost?
This is literally asking for keyboard shortcuts, which can be find wild-spread over the internet. While I do agree that there is an outstanding answer on AutoHotkey; there isn't really a way to determine whether some keyboard shortcuts provide a bigger productivity boost than others. Even better, this depends on the work that you do; you can imagine that in Excel other keyboard shortcuts can make you more productive than the once you use in word...
Hence, this question is not constructive; it is too simple in terms of finding them as a general reference and it is bad subjective in terms of determining what keyboard shortcuts provide a bigger productivity boost.
Can that question be made constructive?
You seem to have gotten two types of answers; of which, interestingly, the other types of answers (of which you accepted one) are constructive. I would thus suggest you to reshape your question to those answers for it to remain open, which shouldn't be very hard to do:
How do I get more productive from using keyboard shortcuts?
There are a lot of keyboard shortcuts available nowadays. How do I determine which ones are the most productive? So, that I could focus on using them more. How can I replace frequently used actions by keyboard shortcuts so that I can perform them more quickly?
This question has multiple benefits:
It's constructive, you won't get a canonical list of shortcuts you can obtain elsewhere.
It actually boosts your productivity, as you get more useful information out of it.
There isn't any subjectivity; you learn to objectively determine which ones make you the most productive, and you will get to learn how to get things that aren't accessible through a keyboard shortcut to be accessible to a keyboard shortcut.
You will get quality instead of quantity; answers that are clear, to the point and useful!
Does that question still have to be made community wiki?
Let me quote Jeff Atwood whom has quoted Grace Note:
Most of the time, you should be asking yourself “How can I improve this post so that community wiki isn’t needed?” Community wiki is like a cheese knife: it is a specialized tool to be used sparingly, and only in very specific circumstances.
Is the resulting question still a specific circumstance that requires Community Wiki? It doesn't seem so.
Remember, as Robert Cartaino often notes; we get the community we shape. Do we want a community filled with community wikis that contain canonical answers that do not make us productive; or do we want a community filled with quality questions and answers which do help make us productive?