I think you can talk or over explain too much on any topic. A few key's to effectiveness are short, concise and complete sentence's.
I think also over complication can be caused by to much communication leaving others more confused by what has been communicated. As well as not getting the right point across by going off on tangents which are not related.
The disadvantages pf effective communication is when employees and their employer can't run a business smoothly because they can't get along and never listen to each other