There should definitely be a monthly event where you actually get engrams from picking up the tags in Supremacy. Where you have to get enough strange coins to enter or something and the event is open for a weekend every month. There would be a real reason to play that game mode and sweat like crazy to try and get as many kills/engrams as possible. I think it would be a lot of fun and if nothing it all, you'll come out of it with a good amount of weapon/armor parts. I can totally see myself playing it and talking to friends about the loot we got.