Aer Lingus also have a similar "plus" fare across the network now. Its £17/€20 as I recall, but there is still a small change fee + fare difference. Seat selection, bags and FFP points are also added in.
I think there is a move to tailor products for different sectors of the market. In reality it is do different to the supermarkets. You can have M Savers Baked Beans, Morrisons Baked Beans or The Best Baked Beans, each catering to a slightly different demographic.