Halo 2 and 3's ranked playlists created a massive, massive cheating incentive and black market revolving around their games and headaches for Xbox Support due to people giving each other account details for boosting. People also scummed new accounts constantly, which they had no way of ever actually preventing, and ruined matchmaking since it was impossible to lock in skill that quickly. It was confirmed like, a year after 3 came out that their next game (which we didn't even know was Reach yet) would no longer have visible ranks.
Reach was set up to encourage you to not account scum, with the long haul rank buildup, and resetting the Arena ranks via seasons. This meant you couldn't boost or buy a top rank account and then just sit on it, it would go away in a couple of months, which made it no longer economically viable to sell boosted accounts.
Arena was also a bit clever in that they did not show you what division you were in until you fed Trueskill enough games (30) to figure out a good idea of what your skill actually was. This is why they had the "play X games for the day" mechanic. It enforced the TS minimum data but also encouraged maximum playlist churn.
I wrote a really big post about it on HBO back then, but considering the context, I really don't miss visible ranks at all. It was so bad that Nintendo never implemented visible ranks in Smash because of what happened in Halo. Epic REMOVED 1-50 visible ranks from Gears 2 and switched over to a pure XP system. Visible ranks are less important to the public than people think; quality matches are more important to player retention.
Personally what I wished we had was something like Halo 3's playlist XP, where you could see a playlist specific EXP amount. This gave me a better idea of how decent someone would be at a specific playlist than their number rank. The data is technically there for Destiny via the Grimoire.