Impact of removing Google+
If you use the name and photo from your Google account on your YouTube channel, your channel content and visibility won't be affected whether or not you have a Google+ profile. Adding or deleting a Google+ profile will have a minimal impact on your channel. Learn more about YouTube features that still need Google+.
Learn more about deleting a Google+ profile from your account.
If your channel is connected to a Google+ page
If your YouTube channel uses a different name than the name you use on your Google account, your channel does need to be connected to a Google+ page. You can't delete a Google+ page that's connected to a channel. You first have to delete the channel.
Remember: YouTube (and Google+) are services that depend on the existence of your Google Account. If you delete your Google Account all products and services attached to that account, including YouTube, will be deleted as well.