Well, Githyanki aren't very sentimental and mind-wise always at the next enemy's throat already, but I agree that this ending wasn't very satisfactory. Also, while I always thought my Tav (a gith herself) would support Lae'zel's comet campaign with all her might, it's being assumed that we join as a simple soldier. Instead, I guess we would have started our own Crèche with lanceboards and owlbears, and the ra'stil we made on the way.
