A user expects after selection an email he will be able to see the content of a mail instantly. Sometimes with 4:4.5~20100910.1175630-1maemo6.1174786 it takes ~5-10 sec until header and content are displayed. If it's not possible to improve the displaying time the user should get some feedback that his mail is loaded currently. Reusing the loading icon from the list view would be a significant improvement in this case.
Display during message download has been improved in commit 6820e99 on 2010-12-29.
It's much faster then before -> closing