I would say that this is already visible by looking at the merits, or the content of the posts themselves. Along your line of thought, it may be nice though to have the merit counter doubled to show total number of earned merits vs to number of merits. That would be an indicator to what you say.

It could go down a level and have a number of merits earned within the board you are navigating (i.e if you are on the Bitcoin Discussion section, you’d see the number of earn merits within this board for each profile that posts there). This may be more useful, since it gives you an indication as to how good the poster is within the conceptual topics of a particular board, regardless of his overall merit score or overall earned merit.

Something like: (22) 120/ 220 -> has earned 22 merits on this board out of 120 earned merits. In total has 220 merits.