Wouldn't really have thought so.
Take your brain (please! take it!):
Like your brain, the R&D department is part of a complex system that does a lot of important stuff. You can argue that the R&D department is the most important part of a company, not least because it couldn't survive long without it. I think the same thing about my brain--but I'd still be just as dead without my liver. You certainly can't prove anything about my effectiveness as a journalist by pointing out that it weighs less than my bones.
So how big should a "brain" be? Hard to say. But let's look at some companies that are generally recognized as pretty innovative, and their R&D as a percentage of revenue:
Apple: three cents out of every dollar
Google: ten cents out of every dollar
Intel: fifteen cents out of every dollar
Genzyme (innovative biotech startup!): sixteen cents of every dollar
US Government: three cents out of every dollar
The article's here, with links that back up those figures. By Megan McArdle.