These are the changes for Twenty Ten 1.2:
r15520 – Make sure we have a header image before showing it.
r15658 – Fixes header positioning in the IE9 beta.
r15532 – Fixes some font issues in IE6 due to incompatible selector.
r15609 – image handling adjustments, which should fix some issues. See #14303.
r15762 r15763 – Use get_template_part() in single.php, attachment.php, page.php, onecolumn-page.php. Introduces loop-page/single/attachment.php. This is a backwards compatible change, as any child theme currently overriding single.php or loop.php will be entirely unaffected. Child themes can now override the loop in these files individually, by using loop-single.php, loop-page.php, or loop-attachment.php. (In loop-page.php, they can also use in_page_template() for the extra level of context.)
These will now be backported to the 3.0 branch and Ian Stewart will soon be preparing a zip file for the themes directory.
If there are other outstanding issues that should be addressed in Twenty Ten 1.2, please link to them in the comments. Otherwise expect a release soon.