AjiNIMC - 5:15 pm on Feb 19, 2012 (gmt 0)
These are the issues, you might face if you remove sitemap, or if you have a bad sitemap.
If Google becomes depended on your sitemap and then if the sitemap stops working, it can end up not crawling some of the new pages. It happened with me but that was around 2 years back ... now may be better.
Sitemap helps you rank better esp if that is realted to keywords that falls under "QDF". [youtube.com...]