This is an often requested feature which has been in our Roadmap for some time (see here and here).
The reason why it’s taking a while to implement is that we want it to cover all possible requirements. Some want to be able to hide some inputs completely, some want to always show them as readonly, some (like you) want to disable them only for specific roles (for example, disable for Content Editors but enable for Content Managers or Admins).
We will definitely look at this in the nearest future.