The RNC itself was different because of the tea party. Have to control those fringe elements you know... And in 2012 they had some more experience. (Also at the time there was talk about electoral vote shenanigans involving Ron Paul delegates so they were most likely feeling paranoid.)
I would say they lost both the 2008 and 2012 elections because of the unpopularity of Bush, rather than any sort of fault in the philosophy of leadership of the party however. In his first term Obama managed to not do anything terribly controversial or upsetting to independents and so 2012 was decided by ephemeral spin regarding social issues and the economy.
2016 will be different, the drone program has received attention, Benghazi incompetence, continued sectarian violence in Iraq, Afghanistan, abuses of power regarding journalism and the IRS, the ill-conceived push for more national restrictions on gun rights will have jaded many, and after two terms all the unrealized ephemeral spin that was hoped for and not forthcoming will also take it's toll on the Democrats... It will be interesting to see how they deal with their situation.
Being the incumbent party is sometimes a liability.
For the Republicans to capitalize on the situation going forward hopefully the Bush legacy will be in a little bit better context, the tea party will be a bit more mainstream, and the RNC a bit more fair and balanced.