Just a few thoughts.
I've been a member here a long time, the comments option is fairly new; it doesn't impinge on my d/l process (I don't notice it).
Whether I'm particularly impressed by a mod or have a problem with it, I typically email or PM the creator.
As with many games, I download anything that seems interesting. It may be weeks, months, or longer before it is actually added to the game. I can make no useful comment until I've tried the mod, and by the time I have it is simpler to contact the creator than to search through the library for an "old" download to post a comment there.
On some sites with comments on downloads those comments are rarely informative beyond letting you know how many people "commented", as opposed to the actual download count. For example, pages of posts merely containing "Thanks", interspersed with emoticon posts (whether a single happy face or multiple lines of happy faces, thumbs up, flag waving, etc.); of course there are those rare comments threads where people, including the creator, discuss the mod, ways it could be improved, incompatibilities, etc.
One site has an interesting addition - a "Thanks" button between the download tally and the comments section, clicking this adds your name to the list and increments the Thanks tally:
Bottom line, just my opinion, of course, a comments thread is useful when it is interesting to read.