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In OTL the Sultans of Gujarat never brought their full military support to the numerous sieges of Diu. Diu seems to be the major issue because it was the Strongest Portuguese fort in the area, it also was the main port for Portuguese customs collection in the area. The Gujarat ports of Surat and Cambay would be able to once again resume trade without Portuguese threats of piracy.
The following source is very extensive in describing the situation, the author suggests that without the logistical network in the area Portugal would suffer a tremendous blow to its military force. Gujarat could then return to dominate trade in the region. It would likely be able to defend itself from the Mogul Empire.