I'm not really sure how rigorous the training is - I do know that many folks educated in Pakistan have a hard time passing their step exams here and some have to try multiple times. Maybe that's a reflection of the training there, or maybe its more of a language barrier? Regardless, the Indian candidates have a way easier time, so maybe there is some level of quality improvement that can be accomplished in Pakistani medical schools
I honestly don't know about indian doctors but all the pakistani doctors I know of from Agha khan, Dow and King Edward in US have passed the steps in one go and that is talking from my very own personal experience.