Probably just me, but I never got the impression that Sting or Rogue were strong at all... Throughout the fight, I believe Natsu and Gajeel were testing out their abilities.
And with this chapter, Natsu put an end to their bullshit.
Not surprised at all, with anything in this chapter.
Awaiting the "epic moments" of Gray against Rufus, Laxus against that lightning faggot, and Erza against that skank bitch.