Not a good sign for 2016...
This.
Sure, the demographics are a problem. In a ever-changing population, a seemingly anti-immigrant, traditional, almost paternalistic, message isn't going to appeal enough for it to be electorally possible for them to win.
As far as I can see - the GOP are lacking in any ideas. Their whole message is based on their opposition to Obama. Despite the President's shortcomings, the public clearly rejected Republican ideas in 2012, so the same attack message isn't going to work in just under 4 years time.
It will be 2020 at the earliest that Republicans may actually be able to a positive case for them to be elected nationally. The biggest shame is that a weak opposition means poor government - and that's only going to have a negative effect on the whole country.
The GOP is not anti-immigrant but anti-immigration reform to people who either came here illegally themselves or brought there kids illegally along with them. Its still not good to be anti-immigration reform with hispanics even though the GOP's base loves that kind of thing.
Like the Dems didn't run against Bush W. when he is in office as opposed to your saying that the Republicans are running against Obama? The Dems disliked Bush W. nearly as much as the R's despise Obama.
As far as the GOP lacking in idea's here is one idea they should cut out is the tax cuts for millionares rhetoric. Maybe Obama not renewing the tax cuts for the upper 2% did them a blessing in disquise. This way its not an issue anymore. Just entitlement reform is the topic at hand.
As far as the topic itself the GOP can keep the religious right as one base of its support but it can't be their only base of support.