I recently had a very similar problem with my drivers side door touch pad. It would intermittently work and I had to press in different spots to get it to finally command the door to unlatch. --Frustrating and embarassing, especially when you're in a hurry after filling up!
I purchased a new switch for less than $20 online and installed in less time than it takes to write this up. Voila! It works perfect every time now. Of course, it makes sense--the drivers side switch gets a lot more use than the passenger side, so it's bound to have a higher failure rate.