I came to know that even within the economy class, there are two-three options for the traveller, but I don't know if that translates to bigger area for your seat. I travelled in Qatar Airways Boeing's few months back and both of them had 17" which I guess is the standard. From BOM to Doha,Qatar it was Boeing 777-300ER and from Doha to CPT, South Africa it was the Boeing 797-8 Dreamliner . IF it was an Airbus would the seat width have been be a bit wider or that's standard for Economy class configuration. If memory serves right, it was 3-5-3 in the first configuration and 3-4-3 in the latter long haul flight.
So looking to know how different is it in Airbus on Economy class.