Echoing @rleshner thoughts here and agree that it makes sense to stick to option 1 and follow the strategy outlined in CIP-3.
While we may not see a notable change in migration behaviour, we expect the new net borrow APY indicated above from Option 1 to at worst invite new users and at best be significant enough to begin migrating users from v2. Furthermore, if Option 1 is chosen and we continue down this incentive path until some acceptable migration threshold, I assume protocols/users will seriously begin to consider migration.