4:3 ratio GONE

From the Home page under quick Actions, there is a Resize image option. In that if you click the Resize for box and chaneg to Stndard then there is Presentation Slide 4:3.

However, that isn't in the resize options once you're within the project window. Then all the measurements are given by number rather than ratio. There is a great long list to choose from though, if you scroll down... Yes, the social media options are most prominent but there are all kinds listed below.

If you would like to see ratio resizing within the project area too please do suggest it on the Uservoice. This gives other people also the chance to see it and vote. 

https://adobeexpress.uservoice.com/forums/951181-adobe-express