That's correct. A client requested a field for phone number but I'm unable
to assign it to be visible when viewing the comments left in the admin.

I can see how complex it could make it but only allowing access to certain tabs of the settings would be what we're after I feel. For example, the only areas I would feel 100% comfortable with clients being able to access would be the General Settings tab and the Meta tab. The rest of it is really not something they are likely to need to get into and is probably more confusing to them.