Make a thread about the T70 and we will talk about the T70 until then, this is about flares and although it has already been said:
"Just because something else is OP doesnt mean this should be"
That's just another example to help you understand that "OP" is just what you think but not necessary a bad thing in a game design, and the role and purpose of flares are quite clear and nerfing/removing them would just destroy the whole structure of the OKW and Axis side in teamgames.
But I think it might be easier to just escape the whole debate and crying out it is "OP" because it can't be counter (like most of the non-plane capabilities?) and can be deployed on the whole map (yeah I suppose commander capabilities are meant to be passiv camo and not influence the game whasoever). And as you pointed out, it has been here for a long time, and claiming suddently that it is OP without even stating a single number seems rather bad in a balance perpesctive, but feel free to continue.