Even if I don’t particularly like the new Blogger design, there’s no doubt that’s where the new features will be added, as the old version will be eventually retired. For example, I recently noticed two new things added to the post editor, although for now only in Blogger in Draft:
First of all: the option to open links in a new window has been added as a simple check box to the ‘Edit Link’ dialog. It’s a nice small update that can save a lot of time and manual tinkering with the HTML code – and, might I add, WordPress has had this option for some time. I made a habit to have links to external sites open in a new window / tab, because this way the reader can easily return to my article after reading what I referenced. The same thing is valid for large images; overwriting content with other sites or images interrupts the visitor and causes unnecessary delays by loading the original article again when (or if) the reader returns to finish it. But if the linked sites are opened in a separate tab the reader can simply close it and return immediately where he left off.

