You will certainly receive many answers. This question is very good.
We are speaking about the tags when you try to type them for a new post, for instance in the Dashboard.
When you type the tags, you get the proposals. I think this is a good feedback.
However, it could be possible to create even the better algorithm how the tags will pop up. Right now the tags will pop up based on the first letters you type.
So you can catch you eye on these proposals. This may be all you need.