Hillary isn't losing PA to Romney. That's just beyond absurd.
Pennsylvania's been trending more conservative relative to the rest of the nation.
Hillary's likely to be in a worse position in 2016 than Obama in 2012, since he was an incumbent seeking reelection, and he's generally agreed to be a superior political talent.
Romney got okay results in Pennsylvania despite relatively little ad spending. Given the electoral value of the state (the Republican who wins that likely wins the election) that is almost certain to change in 2016.
A 1.5-2% trend for a couple cycles really is not a long term indicator. Clear trends are what's happening with the GOP in West Virginia and Dems in Virginia. Pennsylvania the last two cycles is more noise than a rightward trend. I think with Hillary it would trend 2-3% D and be back to around 4% more D than the country.