Theory: Riot is not using 1200 as the target value for the soft reset
Everyone seems to be getting placed much lower than expected. There's two potential reasons for this: Riot isn't normalizing around 1200 or the divisions for ranked are not based around mmr but instead use percentages of the player population. Having flexible division boundaries just makes no sense and should also be pretty easy to test out - a fresh 30 will not get b1/s5 after going 5-5 if placements are done right now.
This pretty much explains all of the anomalies people have been reporting - plat getting placed in silver, silvers getting placed in mid-bronze, etc. Try it yourself if you have the mmr calculation spreadsheet handy.
EDIT: I'm using the formulas found here
replace 1200 with 0