I really don't see how Hornqvist is a bigger issue than Kessel. Kessel is much more of a liability defensively, far worse forechecker and his passing is nowhere near what it was in his best days. He also gets to play with Malkin and even this inconsistent version of Malkin is a far better playmaker than Bjugstad. Yes, it's a problem that Hornqvist has gone dry for so long but Kessel is a bigger problem, he needs to start scoring and make assists like that to McCann on a regular basis, not once in a blue moon.
Also, Hornqvist's scoring was perfectly fine until his concussion, he could still be feeling some after-effects for all we know. And the way the third line is playing, it often gives us momentum even when it's not scoring, when was the last time Kessel has done that? When was the last time the opposition looked scared of Kessel's shot? Last year? He only has three shots in the last three games, by the way, he seemed to be back on track at least in the number of shots department before that but has reverted to passing shot opportunities once again.
I wouldn't mind trying Horny with Sid a bit, he needs to get that even strength goal monkey off his back, once he does I think there is a pretty good chance he will start scoring regularly, I can't say I feel the same about Kessel but I sure hope I am wrong because we really can use his goals right now.