It seems rather useless and superficial.
Let's be honest, when you propose a change to the games balance, you don't really care if IronStylus or KateyKhaos looked at it, you want to know if someone like Morello looked at it. And while it might be interesting to see these indicators for the first week, they'd quickly lose all meaning as you realized that Joe the Intern is also making everything as "Seen by Riot".
The OP one is slightly more useful, but often times if you don't get a reply it's because there was nothing worth saying. Either your comment was too neutral for anyone to care to reply, summed up things perfectly and got up voted a lot, or was seen as complete and utter nonsense and was down voted a lot.
The other flaw with the idea is that they only work if the person is logged in. Riot has stated many times that often they like to sit back and watch discussions, taking notes, rather than jump in on a great discussion and hijack it with comments like "Look at my post!", "East Coast server when?!", and " U.R.F. now!!! ". If a Riot viewed tracker was implemented, many at Riot would probably view the forums while logged out.