It really doesn't matter who really deserves the credit for the victory. Gilkarg planed and commanded the attack. The glory was his to take.
Ahh but it surely does matter. Remember, we're discussing why he got executed, and what effect that "great victory" would have had.
Thinking as the Emperor, if you feel that Gilkarg got lucky one time thanks to a new development and the enemy's stupidity/lack of preparation, and then proceeded to screw up finishing said enemy off for 20 years, would you keep him around? Also keep in mind that even with that one bright spot, Gilkarg still failed. He promised a swift knockout punch. He delivered a costly and prolonged war.
What post war cats could say about the war in hindsight woudn't weight on a decision taken 20 years into the war...
Perhaps; but given that they're still at war 20 years later with no end in sight, it can't have been that great of a victory.
Then, the blame should go to the Emperor. It was the Emperor who ordered Gilkarg to stand down and not press the advantage in McAuliffe's aftermath. That was exactly what Confed needed to get back on its feet.
There was 20 years between McAuliffe and Gilkarg getting executed. Certainly you don't think that the decision to stand down after getting bloodied badly at McAuliffe is the only reason that the Kilrathi were locked in a stalemate?