Currently it is possible to pin posts only to the home page, which is neat and a good feature for major updates/changes. However we are missing an option to pin posts only in channel. Or stick them on top.
For example we have "Support" channel and we would like to have a sticky post with FAQ that will be on top always. Here is quick example how it could look like 
You could argue that there is "Posting Instructions" for each channel (good feature), which kinda covers this scenario. However it does not work if visitor is guest and has no account.
Which basically means that important post(s) will be eventually hidden and not noticed by visitors.