I really don’t like how you can’t craft concrete slabs and stairs. That basically means that we don’t have ANY colorful slabs and stairs. I really wish Mojang will add this because that would allow people to be more creative with what they build.
Edit: As you guys have mentioned in the comments, terracotta could use it as well.
Edit 2: They could also use walls, that could even further build options, and when it comes to build options, the more the merrier.