We've known about some undesirable features of Google+ commenting, for a while now.
- No ability to moderate comments, made against your blog, before they are published.
- No ability to moderate comments, from the dashboard.
- No controls for moderation, or for notification, of comments.
- No ability to view all comments, made against your blog.
- No ability to block all undesirable comments, made by people who don't like your blog.
Not every blog owner realises that anybody in Google+, able to view their blog, can make comments about their blog. Unfortunately, just as you can't see the posts made in Google+, by people not in your circles, neither can you see comments made by people not in your circles - even if their comments are published against your blog.
Deciding that Google+ comments may not be their cup of tea, some blog owners decide to revert to Blogger native commenting, and recover normal commenting features.
Reverting the blog, to use Blogger based comments, is simple enough - in most cases. From the dashboard Google+ menu entry, look for the selection "Use Google+ Comments on this blog". Un checking that selection, your blog is back to native Blogger comments. To verify success, you may need to clear browser cache, and restart the browser.
Some blog owners think that deleting their Google+ profile, or simply reverting their Blogger account, will immediately recover control of commenting. Having deleted / reverted the Google+ profile, however, the Google+ dashboard menu entry disappears - but the blog continues with Google+ based comments, and with no dashboard selection to "Use Google+ Comments on this blog".
For any blog owned by a Blogger account with a newly deleted (reverted) Google+ profile, the blog owner must now again upgrade the Blogger / Google profile to Google+, and create a new Google+ profile. With the Blogger account again using a Google+ profile, the dashboard Google+ entry, with the necessary "Use Google+ Comments on this blog" option, will be restored - and Google+ comments can be disabled.
If you decide that Google+ based comments don't suit your Blogger blog, you can recover normal Blogger comments - but please recover carefully. Always uncheck the dashboard option to "Use Google+ Comments on this blog", before doing anything else.