[mst]

The migration tools I work with have this already automated and (having been involved in the design of said automation) it's really not that difficult to add.

Other DBMSes often have to do complete table rewrites for certain types of ALTER anyway - so while, yes, it's faintly annoying to have to do that in userspace rather than having the db engine do it for you, it's not nearly as big a disadvantage as it first appears.