Auto-generating a revision in 1.3.3 does not pick up any changes, however after upgrading to 1.4, every MySQL dialect type column generates a revision such as this one:

    op.alter_column('comp_details', 'market_type_id',
               existing_type=mysql.INTEGER(display_width=10, unsigned=True),
               type_=mysql.INTEGER(unsigned=True),
               existing_nullable=True)

Here are the column definitions for that one:

    market_type_id = Column(INTEGER(unsigned=True), nullable=True)

I only use the mysql specific integer types, so am unsure if this manifests with other mysql dialect types but would be happy to dig deeper if it would be helpful.