Most important player on the pitch and you don't have two specialists? We have at least 6 back row forwards (more if you count Singleton and Cuthbertson who sometimes start at 13), but only one actual hooker?
Burrow is the problem. His ability to "fill in" for a spell at 9 and his now complete inability to play 7 has meant that to shoehorn him into the 17 we've not had a nine starting and one on the bench. Who would want to be the second hooker at Leeds? You'll never get a game.
When Aiton broke his arm last year we went from being virtually untouchable to a side running on empty, squeezing by the absolute narrowest of margins across the line for the LLS and the GF. Burrow can't play as starting hooker but while we have him he has to play 9, or backup 9 because he can't play 7 anymore.
Some might say that you don't discard players like Burrow while there are miles in the tank, but the disruption to squad planning over the last few years because of that has been significant.