IMO, there should be one SBMM or RBMM playlist. Everything else should be CBMM, except Trials, which should be card progression (no pools). I can understand why people want to play other players around their skill level (I prefer that myself), but it can only work with a high population, so it really needs to be a single playlist that attracts a lot of players. Bungie pandering to players who want everything their way is why we have constant flip-flopping on matchmaking (as well as a bunch of other things). The only sensible compromise that I can see is to have playlists built for types of players, rather than trying to make everything for everybody (just not possible).