Just to sound like an elitist asshole for a minute (an elitist asshole who is correct.) I see a lot of writers groups… and wait, you already know my stance on writers groups. So let’s move on to writers seminars and shit.
Why the fuck would I EVER pay someone 500 bucks to tell me how I should be writing? This is part of the downfall of the craft of writing, everyone is concerned with making a buck, they didn’t stop and think about making something that’s…. I dunno, creative? But to pay someone hundreds of dollars for such trivial, mundane… and WRONG advice is just retarded. If you’ve ever done such a thing, payed money for some “professional” to tell you what to do, please pay me a hundred bucks so I can tell you how fucking stupid you are.
I swear, whatever happened to just learning what works for YOU? Oh wait, I guess that takes way too much work.
I’ve said it many times screenwriters by nature are extremely self centered, looking for that sale… again, losing focus on what’s important… writing something you can at least be marginally proud of. Asking other screenwriters for advice on how to do stuff not format related is a huge mistake. Asking folks to read and give their thoughts is one thing, but asking how it should be done is another.
I don’t think Michael Bay and M. Night don’t make very good movies, but I do give them an assload of credit for bringing the passion into their world.
I think a big reason behind all of this is the fact that people are afraid to fail. But guess what? As a writer, you have to fail again and again and again and again until you stop sucking. If you’re not willing to give that kind of commitment, stay the fuck out of that line of work because you’re just making that shit cluttered.
Wolfen Films 
There are major exceptions to that, like HUGE ones. If you get a group of reliable people together it can only help your writing. The writer should never EVER ever be the sole editor of their work. You’re too close to it as the writer and you’ll either be too critical or not critical enough. The key with groups is to know what advice to take and know to scrap the majority of it.
And while I agree with seminars put on by famous people, seminars are a great place to keep your finger on the pulse of what’s going on. It’s a matter of which ones you attend.
Neither of these things should be part of the generative process, so I agree with you somewhat, but if you’re doing it right revising and editing (two different things btw) should take you far longer that the initial writing.
PS- Thanks for the Blogroll link! I’ll get you on ours asap.