You should be able to post characters from any language, using any version of Writer. If you're seeing problems, it's more likely to be because of encoding issues between Writer and your server, rather than anything specific to the version of Writer you're using. What kind of blog do you have? (Blogger, Windows Live Spaces, etc.)
With Arabic, there is a difference between the Arabic and Hebrew versions and other versions of Writer: the Arabic and Hebrew versions have buttons on the toolbar that let you change the default text direction for the current paragraph, between right-to-left and left-to-right.
If you have feedback about what it's like to use these buttons we'd love to hear it, we don't have a lot of feedback from Arabic or Hebrew bloggers. Thanks.