I was just reading this post from Martin Fowler on the common complaint that Patterns are not new. Fowler says
Not just is this true, but it's the whole point of patterns.
Patterns are there to capture knowledge from the field, not to present original ideas. As a result it's inevitable that patterns books aren't going to add stunning new ideas to those who have been working in a field for a while. But even so I think there's an important role for patterns books even to those who don't need to learn the ideas. This role is to help the experienced people communicate their experience to those around them who are less experienced. Few teams consist of entirely of seasoned developers. One of the most important things an experienced leader can do is pass on her skills.
I would add another role of Patterns for experienced people. It kind of allows you to put your experience in a structured format, not on paper, but also in your head. As you code, you learn certain patterns that work well for certain situations. These are in your head in a big mess and mostly you choose the correct algorithm in an intutive manner than by looking at all the thing you know. By mapping your experience to a existing pattern or to a pattern like structure, you can choose an algorithm in a better manner and put your experience to better use.