Is there a way to implement a rating system for a topic?

Yes. I mean, there is always a way to implement something ;-)

I think the most efficient and easiest system to implement would base the rating by the number of page views. So there could be a link to:

Most popular topics in the last 24 hrs
Most popular topics in the last week

I think what is suggested here is actually a "manual" rating system where users could give a topic some points, pressing +1 or -1 for example. Like a "topic karma".

Page views can not be taken into consideration when building some "practical" rating, because in miniBB this setting could be faked easily. We ourselves are not paying attention on how much topic has been viewn, because forums software has another purpose.

The only one thing which gives the impression about the topic, is how actively it's being discussed, i.e. how many replies are inside. But this is already available and could give some point to imagination.

Manual ratings may not be a good solution. People may do anything to have a better ranking for their topic. Besides, in "Statistics" page, there are links to the Tops. I think those should be enough.