Here you got my workaround to add the TinyMCE to the Blog as well. You have to add a class to the textarea of the blog post. so you have to change /ow_plugins/blogs/controllers/save.php
On Line 200 :
$postTextArea->setSize(WysiwygTextarea::SIZE_L);
You have to add below this:
//Start Class for TinyMCE
$postTextArea->addAttribute('class','ow_blog_post_area');
//End Class TinyMCE
And you have to add the selector to the TinyMCE settings, you can do this with this MySQL Statement:
UPDATE ow_base_config
SET `value` = '|ow_forum_post_area|ow_blog_post_area|'
WHERE `key` LIKE 'tinymce'
AND `name` LIKE 'editor_selectors'
This worked on my newest installation:
http://oxwall.gibts.ch/blogs/post/new