This is great news. 
Currently, like many others, I use CSS to change the colour of menu buttons so they stand out and are more obvious to a users. Specifically menus that “Add” a new record.
The additional options are great and will allow for more variation than I currently have. I like the underline option, this looks very modern, in my opinion. 
I can’t offer any additional feedback about other options for formatting. I’d be very happy with the suggested options being planned. 
With regards to menus, and I appreciate this is not related to formatting. I’d welcome the ability to be able to set, at the app level, forms to be true modal pop ups and redirect to parent by default.
Almost all my forms that add a record redirect to parent rather than showing a confirmation message.
Having modal pop ups set so they can’t be clicked away from which looses any data being added would also be welcomed. Like most I use a bit of JavaScript to stop this.
I appreciate the last few items are not related to the topic but there are a number of things I’d love to see addressed now we are past the bug fixing and into new features. For example, setting the date and currency format at the app level.
All that said, this is really exciting and welcome news. It will save me time not having to use custom code plus give me more options when building than I have now, making apps look fresh and new.