For some people, skydiving is the greatest sport in the world, bottom line. For other people, skydiving is a total pain in the ass and not much fun at all.
People have learned to BASE jump without skydiving. It has been done. However, if you asked anyone who skipped the skydive steps, they will invariably tell you that it was stupid and if they could go back and do it again, they'd skydive a lot more. Some BASE jumpers who got into the sport with only a very small amount of skydiving who now have moderate experience levels in BASE may tell you that skydiving is totally unnecessary. However, pretty much every highly experienced BASE jumper in the world will tell you that skydiving is crucial, and you should believe them.
Personally, as someone who started BASE jumping with only 11 skydives and went to Lauterbrunnen and the Eiger in my first month of BASE jumping, I stand firmly in the belief that skydiving is absolutely and positively important not only in the beginning, but all throughout, your BASE career. Even if it's not even that fun, it's something that I believe should be viewed as necessary in order to reach a competent level in BASE, especially if you ever plan to complete slider-up BASE jumps. I feel lucky to have survived my idiocy and if I could go back in time, I would skydive a lot more. I would have had a lot more fun on my earliest cliff jumps and would be a better BASE jumper than I am today.
If you never plan to jump anything over 400 feet, then maybe you can learn plenty of canopy skills at the Perrine Bridge and in that case skydiving really is unnecessary. I would not argue with that logic, and many jumpers want to do nothing but low jumps - in that case, by all means, skip the dropzone.
But slider-up and terminal BASE jumping, at least for me, is about as fun as fun gets. And I believe that the better you get the more fun you can have. Thus, training in the skydive environment is highly important. If you can't fly your body well, then you can't BASE jump well.
Some people swear by the tunnel and I agree that it's a wonderful tool. However, you can't learn to track in a tunnel, and tracking is probably the single most important skill you will need to master.
Skydiving is going to hurt a lot less if you learn to like it. Don't take the dropzone duschbags seriously - anyone who is disrespectful to you because of your low jump numbers is not worthy of your friendship, or of your attention, so ignore them and their attitudes. When someone farts on the plane, it's usually the guy who thinks he's better than you because he has more jumps, so feel free to blame it on him. I know the bureaucracy sucks, but you'll need to buy the membership and get the insurance; it's not that big of a deal and in the long run, compared to the BASE fun you're going to have, it's a small expense.
The bottom line is that if you want to BASE jump the big walls, but you don't want to skydive, then you don't really want to BASE jump. And to be successful in BASE, you have to want it for real.