I'm very conflicted on this. I would have to separate oral and intercourse as sole entities to answer this. In the case of oral as foreplay for intercourse, intercourse is more intimate. Conversely, intercourse followed by oral, the oral is more intimate. With each on their own, I see oral as very... juvenile. It's what teenagers do as a step in the direction of intercourse. (Aside: For myself this was not actually true, we had intercourse long before before oral of any sort when we began dating.) We do oral as foreplay nearly every session and sometimes it's only oral, but it's often the build-up for intercourse.
Here is the conflict: intimacy is of course what you make it -- oral CAN be infinitely more intimate. It's all in the technique.