I agree that they are clunky but until a suitable replacement is found they do add much value. I shouldn't have to post a comment to agree with someone, or to acknowledge a funny remark.
If one finds that scrolling down to look at who has thumbed a comment is troublesome, one has the option to...
After highlighting this issue on the NSC Maintenance thread, and without any proactive response from the mods on this, I think the problem is with the new layout style. If one chooses the Classic style the thumbs are there. Just to confirm this, are you using the new style?