The cooling pad can certainly give you some extra peace of mind just knowing that it's a few degrees cooler. I have a 2011 13" MBP and it doesn't get hot to the touch ever. It's definitely not necessary.
How do the 13's compare to the 15's? I have a 2011 i7 quad MBP 15 and it gets scorching hot at times. Thinking of downsizing to the 13 but only if it stays much cooler - even on the i7 dual core.