I have a Roubaix Expert triple and there's no problem with shifting gears. I will admit I've never ridden a double with Ultegra STI shifters so I can't really compare the two to determine if the double is actually smoother.

I also live in Socal and in addition to the hills, you have to think about the Santa Ana winds. When I'm riding up a hill into a strong wind, not only am I glad I have my "granny" ring, I sometimes wish I had a "great-granny" ring.