Have to say there are a number of things I'm finding rather annoying with the new comments system:
Harder formatting: you can't do keyboard-shortcuts, such as CONTROL + B for Bold or CONTROL + I for Italic anymore. Instead you have to select the text after typing it, wait for the floating-toolbar to appear above (similar to the one in Microsoft Office apps) and then pick an option there. Used to be much quicker to be able to do the formatting as-I-went-along, not have to do it all afterwards! (Also the "Aa" icon in the bottom-right doesn't work for selected text; it only formats text in that style from the current point onwards.)
Dislikes lengthy comments: write anything longer than a few sentences and be greeted with a message along-the-lines-of "Are you sure you want to post this? Let's try and keep the conversation civil" followed by it then "waiting for approval". It's tedious to say the least -- maybe show this warning once the character or word threshold has been reached, not only after the user tries to post it?
No character-limit is visible: following-on from above, if you write a long post, at some-point it just stops typing and then scrolls down the page. If there is a character or word limit, perhaps consider adding a message like "430 characters remaining" somewhere nearby, like most other sites do?
Profanity / bad-language not made clear: I added a comment about a week ago and was advised that as it contained profanity, it could not be posted, despite this clearly being an error. Might I suggest in such cases, maybe flag any disallowed words in red so users know what needs correcting or changing? (My only option was to guess what it might be, copy-and-paste my original comment into a new one, make said change, then delete the one pending approval.)
Deceiving number of replies shown: the number of replies shown below a comment seems to only count the replies that are direct children of the parent comment, not all sub-replies. For example, assume "Comment A" has one direct-reply, "Comment B", and then "Comment B" has two replies, "Comment C" and "Comment D". You'd expect for "Comment A" to say "3 replies", but it will say "1 reply". Then "Comment B" will say "2 replies" and you have to expand each level in-turn.
Show More Comments option: I can understand how hiding some comments may be useful when on a mobile-device, but on desktop it feels a little pointless to have to click it to be able to see all the comments, especially when sometimes it asks you "How would you rate the quality of this conversation" before you can continue to see them.
Emoji's have to be manually entered: isn't usual-convention that typing :) should convert to đ and ;) should convert to đ ? Yet old-style "emoticons" remain just as plain-text. If not changed live while typing, I'd at-least expect that after submitting a comment they should appear converted after it's posted.