To be fair (and again, I hate being fair), all indications way back when were not that Obama was going to obtain ahistorical support among Latinos. They voted against him 2-1 in the primaries (versus 2-1 for him in the general), and McCain historically had been one of the most pro-immigration Republicans.
Few predicted that Obama would do as well as he did among Hispanics back then
Even back then, General election polling was pretty much showing the GOP brand was deathly tainted among Hispanics. Of course, all the pundits were totally
ignoring that, but the signs were definitely there. I even said as much in this thread. That's why the Nevada polling at the time was so f'in puzzling. Demographically, Obama being 5-6 points behind there made no sense