I suspect that imports, regardless of the date of original & continuous manufacture, will need to comply with the new FDA rules. I don't know if the pre-February 2007 grandfathering would also apply to them. Perhaps a few like MacBaren, as suggested above, may decide to pay-to-play. I think that many would say, "To hell with the Yanks & their FDA!"
Losing all or most of the imported tobaccos would be tragic, especially since most of my favorite tobaccos are imported. It would be almost as bad as losing all single malt's