The migration theory is merely the invasion theory on its death bed, but even it is a great improvement over the usual Aryans smashing Harappa scenario which has captured the imagination of so many people.
The propositions of time, place and people for the Aryan invasion has continually shifted as it has always been a theory in search of facts, not one based on anything solid. The only logical conclusion of the continual retreat of the Aryan invasion theory from a destructive invasion to a pastoral migration is the complete abandonment of it. The continual changes in the theory relative to the data which disproves it only shows the invalidity at its core. The Aryan invasion has gone from a bang to whimper and will soon fade out altogether.