In my career as a writer, I've interviewed a lot of great musicians, and most of them stressed the importance of knowing your fundamentals, because that gives you a strong foundation on which to create your music. Even the people who play free jazz, or free improv said the same thing. My friend, Swiss drummer Fredy Studer, who is well known as an improvising drummer, said something to the affect of, “There's a right way and a wrong way to improvise. You have to know what you are doing before you can play free.” So many drummers stressed working out of books like Stick Control (George Lawrence Stone) and Syncopation (Ted Reed), which are both real fundamental books. BTW, these were chosen as the number 1 and 2 books respectively in Modern Drummer magazine's The Top 25 Drum Books.
And all of this rings so true: how can you play at a high level if you don't have anything to back that up with? You can't! I stress this to my students and try to get them to understand the importance of having strong, fundamental technique. Working on fundamental technique is a lot like athletes weight lifting or running—it's not glamorous, but it needs to be done. It also gives you a reserve of strength to draw on when you need it. Like on those nights you don't feel good, or when things just aren't going right, you can draw upon your fundamental training to hold things together and get you through the gig. And on those magical nights, a strong fundamental background gives you a point to stretch out from, and keeps you anchored, no matter how far out you go.
So when you are practicing your 200BPM Blast Beats, or your 9 over 17 Polyrhythms, just remember it's your strong fundamentals that got you there. Don't forget to keep working on them, keep building on them.