They aim to introduce that in version 3.0, which they say will be a complete overhaul of the app.
Non-destructive editing through live adjustment layers is definitely the single most useful feature any editing software can have.
That alone makes life so much easier.
I remember people saying “3.0 is right around the corner” several years ago.
I categorize GIMP 3.0 the same as ASOIAF, Star Citizen, and the Google Drive client for Linux. I’ll be pleasantly surprised if I see it, but I ain’t holding my breath.