With Obama as president Republicans have more than doubled the number of state legislatures that they control. Interestingly, the 2012 election didn't slow this trend.
Prior to the 2008 election
Republicans in control of 14 legislatures (15 with Nebraska, which is technically non-partisan but is actually controlled by Republicans)
Obama's election in 2008 had impact on the number of legislatures controlled by Republicans, but Democrats did pick up four legislatures.
Prior to the 2010 midterm election (data from NCSL.org)
Republicans in control of 14 legislatures (15 with Nebraska, which is technically non-partisan but is actually controlled by Republicans)
After the 2010 midterm election
Republicans in control of 21 legislatures (22 with Nebraska).
Prior to the 2012 election
Republicans in control of 26 legislatures (27 with Nebraska)
After the 2014 election
Republicans in control of 30 legislature (31 with Nebraska)
To put it differently, while Democrats controlled 23 legislatures prior to 2008, they now control 11. Over that same time Republicans went from 14 to 30.