Most "emerging majority" talk is premature. Those assessments tend to assume that would happened in the last election will happen in the next. They also tend to assume that a voters demographic makeup determines how they will vote. Sometimes it does, but these trends change overtime (and there is always one election where they filp).
As for 2016, the Democrats are still the favorites based in large part on structural factors (the economy, a huge GOP field, a very solid campaign infrastructure for Hillary) and demographic factors, but any talk of being able to govern for eight years by simply duplicating the Obama coalition is unrealistic. The Democratic Party has advantages, but they are by no means the "majority" party in America.
But, I will dispelling the notion about 2018, that it will be another horrible year because, Dems are disadvantaged in the Senate due to more Democratic incumbants remaining. But, Dems are concerned more about reapportionment, and the G O P are term limited in the states listed above, and shall Dems lose the Senate again, the Democratic govs will ensure that there is a Democratic congress in 2020 or soon thereafter, due to the hispanic growth.
