Authorities should use past consensuses to decide how to vote on relay flags
At the moment, each authority decides what flags to assign to each node based on its own memory. This means that authorities that have been started recently have a different impression -- compared to more long-lived authorities -- about some relays .
Something that might make more sense is if authorities used past consensuses to get a better idea about the stability and speed of relays.
Since authorities don't keep past consensuses around, a way to do the above might be to create a script that each authority runs, downloads the past consensuses, calculates statistics about all nodes, and then it creates a file with those statistics. Then the authority loads that file, and uses it to update its knowledge base.
There might be better approaches.