I think some non-writers are a little shy about this because they don't necessarily know what a good critique looks like. Trust me, writers sometimes have all the jargon down and brilliant ideas for exactly how, technically, to fix a scene -- and other times we will look at each other and go, "I dunno, it's just that this part kinda goes whoppita whoppita whoppita when it should go whirrrrrr, y'know?" Or else, "I think it needs to be more, kinda, um, um...manic...does that make sense?" If you socialize with writers you should know that we are not necessarily more coherent than other people until we've had several drafts to hammer out the whoppitas and the ums. And we probably ask each other, "Does that make sense?" more often than the international average, not less. And sometimes the whoppitas and the ums are the bits that make for a good and useful critique and the detailed, technical jargon ideas about how to fix something turn out not to be very useful.
Also writing-related: awhile back people were talking about what, if anything, writers owe readers. And watching Season 3 Veronica Mars made me think of something in that direction. I think one of the things we owe readers is to put telling the current story to the best of our abilities ahead of marketing future stories. And another thing is to do our damnedest to tell them whole stories. The ending may be unresolved, but as long as we're alive and able to work, it shouldn't be unresolved for no reason. An ambiguous ending should be a choice rather than a failure to finish. Because a story is not about the storyteller being able to continue telling tales. It's about itself, and it should have a pretty firm dependence upon the storyteller's tales being worth telling.
The way TV shows are made is terrible for this, and I know that. No book editor in the world would ever look at someone who had written two 100K novels and say, "Okay...well...I might let you write another 100K about these characters, but...give me a 30K novella about them first. Then we'll see if we can tack on a 10K novelette. Twice. And then we'll see if another 40K novella does the trick, and no, wait, you can't have those last 10K; oh well. Hey, you appear to have turned in incompetent directionless crap! Huh, let's see how that sells. Badly. Oh. Bye, then." But the choices Rob Thomas made in the way he handled the impending cancellation of VM were not about bringing the story to as much of a close as he could at that point in its telling -- they were not about giving us the ending of a decent "middle book," say. They were about flailing around desperately trying to demonstrate to the network that he wasn't done telling it. As if the network cared.
I feel sorry for him, but having watched the director's commentary, I just wanted to shake him and say, "Idiot, the network was already screwing you over. It was going to keep screwing you over. And doing a crappy job for the actual viewers, few though we may have been at that point, was not the answer. Dude. You have just been telling two seasons worth of a story about how everything has consequences. I want you to watch the old episodes of your own show and think about what you've done. And for your penance, write me a show starring Percy Daggs as a bioengineer and Francis Capra as...um...something appropriately snarky and conflicted, okay? And Tina Majorino as Mac In A Very Slight And Unconvincing Disguise. All right, you can go now."