I just realized that some of my blazers' sleeves are too slim for french cuffs: there is no room at all between the sleeve and the external part of the cuff. however otherwise they look great.
Does it mean the sleeves are too narrow? The cuffs too wide? or is it normal and depends on style?
I wouldn't say they're too narrow. If you like how they look, and they don't feel restricting, they are not too narrow. Too narrow for French cuffs, obviously, but then, also obviously, not made to be worn with French cuffs.
I'd say it's definitely a style statement from the designer.