We didn't just move the comments to the bottom -- there were a ton of other changes to the commenting system.
Previously you could reply to a comment on the same page, but unless that person was the profile manager, they would get no notification of that comment. You could also reply on their page or send them a message, but without context, they may have no idea what you were replying to. Now you can reply directly to a comment on the same page, and the original commenter and the profile manager can both be notified (depending on their settings). Because replies to comments will be indented (up to 5 levels), the comments were moved to the bottom because otherwise it would be too squished on the sidebar.
An archive feature was added, which allows comments to be hidden once they are no longer relevant, instead of permanently deleted. These archived comments can always be viewed again and un-archived if needed.
We've increased the amount of text that can be left in the comment box. Instead of 800(?) you can now type up to 8000 characters so comments can be longer.
It's also easy to move a discussion that's going on in the comments to G2G. With the click of a button, you can copy the text of a comment to a G2G post if you want feedback from the community.
We also made it easier to flag comments that are spam.
These should all make collaborating on profiles a bit easier, so I'm not sure why you don't think this is an improvement.