Hypothesis on S4 Ranked Placements
Riot is trying to "refresh" the system in a sense. Season 3, there were a lot of people in higher divisions who didn't deserve to be there based on skill, and vice versa there were a lot of players stuck in elo lower than where they should be due to massive clamping. With the Season 4 soft reset, players who were placed in the season before trend towards placing lower than where they were the previous season, but are compensated with the fact that it's now easier to climb and clamping is much less of a problem.
Also, keep in mind that who you play against may not determine where you mmr is. You may simply be a balancing factor in the queue (the low player to bring the team mmr down or the high player to balance out the opposing team having a higher mmr than yours)
As far as I know, this system is working as intended. Majority of the players on my friend's list who placed significantly lower than where they finished S3 had no problem climbing back up to where they were within a week or two of play, and some have already climbed even higher.
This is, of course, just my hypothesis based on observation. Thoughts? Opinions? Confirmation or correction from Rioters?