Well everyone I know including myself has had a heck of a time getting an SEF component to work. As of right now my favorite is ArtioJoomSEF component, but I would like to see the new version of Joomla include a couple extra features for instance, I want full control on how the SEF URL is formatted, and how precisely the URL will finally appear, even after edits. Let's say, for instance, I need the SEF URL to include the section & categories name in the URL, as that's how I divide my contents. Problem is, Joomla 1.5 RC2's SEF features are not consistent in URL creation, sometimes they include and then later exclude the section/category names.
While giving full control on SEF URL creation, SEF should be able to check for duplicate URLs or content & suggest a unique SEF URL for our title, just like an SEF feature on Wordpress or similar.

Very simply: the use of heading tags, h1, h2, h3 incorporated in the standard Joomla tags. For example: the "contentheading" tag being able to be changed to include a h1 tag!

I welcome the day that h1 tags, which I consider a basic and essential optimisation tool, become automatically generated by Joomla.

A fully documented API for all extension developers to work with so that no matter what SEF extension you decide to use, there are no issues with this one working with that one etc. I'm not a developer (yet) so this might in fact be the case, but if not, this must surely be the way forwards. Standardisation to ensure compatibility.

This is a great post and have kept it in my bookmarks. Will continue to read it as i?m very new to a lot of the points you mention!

Thanks though, i?m glad some people share good stuff like this!