I think the reason we should be more careful about
noindex,nofollow is this statement from
google:
1. Reasons your site may not be included.
Your pages are dynamically generated. We are able to index dynamically generated pages. However, because our web crawler can easily overwhelm and crash sites serving dynamic content, we limit the amount of dynamic pages we index.
So since they limit the amount of dynamic content they spider
you want to make what they do spider unique to increase coverage (and to lower the burden on your own server).
Changing everything to have pretty urls would remedy the
spidering scope issue (although it would still leave google
pulling down an order of magnitude too many pages for things
like bug tracker).
