If you ask specifically for discussion and critique, you will usually get some. See Permissions Utility Script for sysadmins - seeking comments for an example.

The difficulty is finding the right sized chunk of code to post: too little and it'll be difficult to criticise the overall design, too much and few people are likely to read enough of the code to give useful comments.

Of course, you can save time by first reading as many threads like the one mentioned above as you can find, and making sure that you have fixed anything that you can learn from them. :)

Hugo