I'd be careful with asking for an overhaul to the first book. Remember, it was when their project started, so obviously they had to start out smaller - yet the scope for the player increased with book 2 and 3 respectively. If you were to go back now to increase the length of the first book, this would be a jump into a rabbit hole that has no end in sight, as then people would ask for improvements for each subsequent book again and again. Besides, Katara was a more than just a simple side character in the 3rd book, giving out small bits of information on the overarching story and the future events (is it past then though, as she already knew and was hiding it from your current self? Eh, time travel shenanigans is never fun to think through) and with her actions actively influencing tophs training.