I like this. It makes things a lot more simple and to the point. Yeah it might break people's maps in the newest update, but really not hard to play 1.11 or even 1.10. Updating to new 1.13 might be hard for everyone though, so still play on 1.12 or whatever update til the next update that entices you comes out. That is what I do anyway.
This is needed for infinite blocks, so i say lets do it.
Although I will miss switching gamemodes in numerical order -;(