Riot, can we get some insight on your "larger projects"?

From the Patch 5.2 Notes:

As we mentioned in the foreword, we're looking into champions who will be heavily impacted, but some of our larger projects (Veigar, Katarina, Mordekaiser) have to wait until 5.3.

Can you guys tell us what "larger projects" means? I think we (or at least I) would love to know both the specific changes you presumably are testing and the scope of those changes.