That’s Great News for People who are using Blogger, They Added a Better “Post Preview” in Blogger Draft not in Blogger, This Preview will open your Preview Post in New Window and will Show you it as it’s on your Blog.
For Who Don’t Know, Blogger in Draft is a System from Blogger Where you can see things and new Settings before they published on Blogger.
On the New Post page, click on the Preview button and you will see a new window open with the WYSIWYG preview of the post. This is how your blog post will appear to your readers when you hit publish, with the same format and style of your current Blogger theme.
This is the preview page after clicking on Preview:
Note: that the preview page does not automatically update as the contents of the post changes.