I think a minimal compliance fix for a 3.3.2 site which doesn't have open user registration is to disable any cookie-using plugins, make sure all your registered users know that cookies are used when they log in, and either: a) comment out the setcookie lines in wp-comments-post.php; or b) amend your theme's comments.php to add a notice that commenting will cause cookies to be set and add a listing of those cookies to your privacy policy (the cookie-cat plugin may help with that). Or you could use a plugin to add a notice to your comment and login forms, but I'm not sure if there is one yet and no-one's hired me to make one.
If there are cookie-using plugins, I don't think any of the compliance plugins I've seen will help (most delete cookies after setting them if consent is refused, which isn't what the ICO guidance says), but I might have overlooked one.
Until the 3.4 pluggable cookie functions are available, I think a compliance plugin would need to be able to stop other plugins running - or delete the cookies before they are sent to the browser and I doubt a plugin can do that (the PHP manual says "Cookies will not become visible until the next loading of a page").
I'll mention it if I see one that does work - and I'd love to hear it if you've tested one that really does work, like no cookies attempted unless you click "I agree".
