I have seen this before - if the paint is applied to dry plaster without thinning it with water - a mist coat - the layer of paint fails to soak into the plaster - it skins over and blisters and then goes flakey.
If it were my room I would brush off ALL the flakey paint and sand the edges and then apply a mist coat - whenever I do this with 20% water I get paint splashes everywhere - then I would look at it and make a decision - I can cope with a few small blemishes - you don't notice them unless you're searching for them - then I'd put the finishing coat(s) on.
Then I'd look at it again.
Somebody told me that wallpaper is becoming fashionable again but not in my house it isn't.
Of course you could always call in an interior decorator and have it done professionally.
You might also inspect the walls in all the rooms - there may be issues yet to emerge...