In fact, there are only two of them:
– ISO and TAQ-V can no longer be used.
– Some bug appeared, and not everyone can equip skins for ranked games, but they’ll fix it (it seems that ranking up also resolves this).
Ranked play has gained significant popularity:
Before MWII, it was a topic spoken of by very few. I knew a couple of guys who played it. Many watched the league just for the rewards, but that’s another story. I see that many are playing it on the channel. Remember, in MW2 they added groups and channels where you can find players (there are also ones for VZ and MV). It’s convenient to see who’s online and team up.
Charlie also noted the increased popularity of MWII on Twitch, attributing it to the ranking system. Are you looking forward to the ranking system in Warzone (it will be available from Season 3)? What division are you in? Do you play ranked matches?