I don't think it is quite the same as the 737; The A320 started out as a fully integrated electronic FBW computer jet. The 737 is an essentially mechanical design from the 50's that has had various electronic gizmos added on in recent years, but never fully integrated. Even now, its systems do not have the full capability of the A320 family.
If Airbus can find more fuel capacity with closer fitting tank liners then why not go for it? That's refinement of a good design.
Last edited by Uplinker; 4th Mar 2021 at 10:20.