The edit suggestion obviously improved the post and should have been approved. I approved it and made some further changes. I also edited the answer slightly.
My take: it is always worthwhile to improve an old post that is not going to be deleted. The age of a post has no bearing on whether it should be edited or not.
The tour says:
we're working together to build a library of detailed answers to every question about Ubuntu.
So let's try to make each post as clear as possible.
As a reviewer, if you come across a post that you feel should be deleted in the Suggested Edits queue, you can certainly take steps towards deleting the post (such as downvoting, flagging or voting to close or delete). In such cases you may wish to reject the edit suggestion, but I think it is often better to approve a good edit suggestion so that other reviewers can take a decision on whether to delete the better version of the post (we shouldn't delete a useful post because of its spelling errors or lack of paragraphs).