Currently the phpBB topic URLs look similar to YouTube's (and they are kind of "human readable"). For example:
A YouTube URL like this one
https://www.youtube.com/watch?v=dQw4w9WgXcQmeans "watch the video that has the id dQw4w9WgXcQ".
A phpBB URL like this one
https://area51.phpbb.com/phpBB/viewtopic.php?t=40965means "view the topic that has the id/number 40965".
I only wish that we'll eventually remove the f variable from the URL. Not only for aesthetic reasons, but also because it introduces a small bug known as "ghost users bug".
The canonical URLs don't have the f variable which means that there are users who are viewing the topics in their canonical form (without the f=) such as those who found them on Google. Those users are not displayed in the who is online list of the specific forum.
I'd rather see that little bug being fixed and the f variable removed than have new "human readable" URLs.