Spats does give some good points that West Punjab (and by extension her Indus peripheries) were outside the pale of Vedas.
However the key question is the question of the Siraiki language.
* More than Urdu being an “Indian linguistic invasion” into the Indus; the Punjabi language also seems to be a Hindawi pushback from the East into the Lahnda speaking West.
* The remnants of Lahnda, which descends from the same Prakrit as Sindhi, are Hindko and Seraiki.
* In a way Lahore functions a bit like Delhi in diffusing a more Gangetic/Indic bias to the Indus region; one Seraiki leaning website claimed that the invading Sikhs brought Punjabi into the Punjab.
* The Punjab and Sindh are disproportionately influential provinces and “Seraikistan”/Bahawlapur would dramatically rebalance the federation (Pak Punjab hasn’t had its Haryana moment yet).
* The question of Gilgit-Baltistan, Hindko and Pathans in Baluchistan raise up more dilemmas as to provincial rebalance.
* The historic Indo-Gangetic axis, the GT road, is Kabul-Lahore-Delhi-Dhaka. Perhaps if our great British overlords had adopted a more sensible approach to the Subcontinent we could have seen many Indias based on these great cities. I don’t know what would have been equivalent cities in the South; Mysore, Hyderabad?
Some interesting links: