Pallaeon did come into his own after Thrawn was killed, and even noted that he carried some of Thrawn with him. It is not out of the question for Pallaeon to go toe to toe with Thrawn, but that would mainly come from his experience in working with the Grand Admiral.
Garm on the other hand. He managed to go toe to toe with Thrawn, but IIRC Thrawn managed to gain the upper hand in their engagements. However, he did hold his own quite well.
Actually Garm was outnumbered in one engagement to begin with, and managed to get his forces out of there successfully.
TBH if Thrawn had been around when the Vong were starting their rampage, the NJO series would have been at most 3 books, where Thrawn ends up doing a savage beatdown. Thrawn and Luke Skywalker on the same side, the Vong wouldn't have stood a chance.