It really isn't about differences in standards - the example about the en suite isn't comparable at all.
I do agree that children can cope better with cattle class as they are smaller and fit into the spaces more easily.
They don't need an en suite just because their parents have one
However I would never leave my dc's in a situation where they had to deal with adults they don't know on their own, whether the cause of the problem was the adult or my child. This particularly stands for a long haul flight where you are cooped up with people for a long time and you have no means of escape.
Once they reached, say, 16 I would consider it but by then they'd be old enough to appreciate business class themselves and would probably get the hump if treated differently.