After a few people made some attempts to use the commenting system (thanks guys!), I’ve decided to keep the CAPTCHA. Overall, people don’t seem to have trouble with it, even if they have to reload it a couple times.
I have, however, relaxed the rules which queue comments for moderation. This was causing confusion for some people, and more time doing admin for me, as I had to approve the comments. Some comments will still be moderated if they look like spam, but that should be pretty rare.
Thanks to everybody who helped out.