it may seem as a strange suggestion, but I would argue that showing the number of people solved a problem can affect your perception of the problem, in other words, it may force you to prejudge the problem difficulty,some people may say only 100 people solved the problem! it must be a difficult problem let's avoid it, others may say 40k people solved the problem, it must be naive boring problem, why isn't there an optional feature to hide the number of people solved a problem same as for tags, it is no big deal, but I think it would be nice to add such feature, and I think problem level (A-B-C-D-E...) could be enough, and it will be your choice anyway