Keldeo can't do much against Toxicroak, Jellicent, or Celebi, the right coverage move on Terrakion help get rid of them
You can add that Dragonite (who is alot more common than Luke) as well as Salamence appreciate Landorus-T and Gliscor gone.
Agree with Fuzznip, Protect has certainly got alot more cons then pros. Even if you manage to scout and are lucky enough fore the opposing Steel-type to be choiced, the opponent can double switch ya know? If you're wrong and they set up Wish/ SD or whatever they are going to, you put yourself iin a pretty bad situation.
At the very least it should be Earthquake / Protect?
Just my thoughts, up to QC though