From my (limited) experience, novels are very different to short stories. You can hold the whole concept of a short story in your head at one time.. but novels are big and slippery. Things change and develop as you write - so you often have to go back and rewrite or even delete huge swathes of things to fit the new pattern and flow. There are some people who can do without this - but IMO they're either brilliant writing geniuses (to whom we should not compare ourselves) or they're incredibly experienced writers who started out by going through the major-overhaul process... but who have now honed their talent so much they no longer need it... leaving us still in need, generally, of rewriting.
This is not to say that maybe you're an exception - or maybe you're much better at planning (and sticking to the plan) than me :)
Followup to: Don't Fear Failure
In the same theme as the last article, I think that failure is actually pretty important in learning. Rationality needs data, and trying is a good source of it.
When you're trying to do something new, you probably won't be able to do it right the first time. Even if you obsess over it. Jeff Atwood is a programmer who says Quantity Always Trumps Quality
The people who tried more did better, even though they failed more too. Of course you shouldn't try to fail, but you shouldn't let the fear of it stop you from tyring.
I wouldn't go as far as to say that quantity always trumps quality, but where the cost of failure is low lots of failures that you pay attention to is a pretty good way of learning. You should hold off on proposing solutions, but you also need to get around to actually trying the proposed solution.
I'm normed such that I'll spend more time talking about if something will work than trying it out to see if it works. The problem is that if you don't know about something already, your thoughts about what will work aren't going to be particularly accurate. Trying something will very conclusively demonstrate if something works or not.
Note:
I originally had this as part of Don't Fear Failure, but that post got too long.