I like this idea very much, thank you!
Independent to whether this proposal is accepted or not, I'd like to point out that it
would be very useful to notify all maintainers of this issue, probably by filing a bug to
every package that uses one of these packages (webkitgtk, webkitgtk3), adding a link to
your statement above and tell the maintainer to take action:
Contact upstream. If upstream will be porting the package to Webkit2Gtk, ship it in
Fedora. If not, try to build without WebKit support. If that fails, deprecate a package by
filing bugs to all packages relying on it.
Sadly, I don't know any way to automate this and filing ~50 bugs is quite much.