This is going to break a lot of websites.

For end users who barely understand how plugin updates work, they will likely do a mess. Guaranteed.

An for those of us being webmasters/managers of hundreds of WP sites,... man you are making us working a lot of extra time FOR FREE!!!! This upgrade cannot be taken lightly and a lot of testing must be made in a per site basis. Customers shouldn't be charged for this. But they will. And even more: a lot of customers/endusers will probably choose to do-not-upgrade-my-install. How about that?