Something like that could be an option; see also this other comment.[1] However every time I've thought about "hey, what if we made the 20% better by...", my conclusion has been "oh, but then we might never recommend [items with some set of properties that should get recommended], and the algorithm won't be able to correct itself." Any time you try to optimize in a certain direction, you'll always introduce at least a little bias[2], and randomness at least gives a chance of breaking out of that. So something like this could be a good idea, but I wouldn't want to have it completely replace random recommendations.

[1] https://news.ycombinator.com/item?id=27669863

[2] This experience has affected the way I perceive advice from people on the internet