1. He ran as "not Obama"
Yep. I was worried about this and this looks like what did him in. You can't just be the "anti-candidate" You have to have some viable solutions to solve problems.
2. The GOP establishment refused to reach out to tea party conservatives and Ron Paul libertarians...so they just stayed home.
Well the Tea Party's name right now may not be very good to associate with these days. I think the Tea Party got hijacked a long time ago and strayed from their original intentions.
As for Ron Paul libertarians, hopefully nominating someone like Rand Paul will help jump start the libertarian movement in the GOP and bring in the libertarians to the GOP in droves. I'm one of them FWIW.
3. Obama garnered less votes than McCain's losing effort in 2008.
This really surprised the hell out of me. Hell it surprised most people.
But really I think Obama won because he had the most superior ground game we've ever seen. If the GOP can fix and improve their ground game, they will be in better shape. I would prefer they do that along with tweaking their platform.