More Tag Types in WYSIWYG Editor

Hey I’m wondering if there is anyway to add more tag types to the WYSIWYG. Currently there are only 3, h2, h3 and p. Is there any reason why these elements were chosen in particular? Additionally it would be really helpful to have the option to add more, Eg h1,h4,h5,h6,span etc. Or even a code view similar to wordpress.