It's the mental power that matters the most and perhaps that's why we failed so many times in the past few years. Was surprised to see Iker taking the pen yesterday since he tends to fail at shooting in general, but he did a lot better than expected.
My pick would be Mikel Rico - mentally strong, experienced, decent technique, sense of responsibility.
Aymeric is also self-confident enough, sometimes even too much, which is due to his age I guess...
Third choice - San Jose. While I'm not too happy to see him on the pitch, he does have a cold-blooded way of scoring which is necessary.
Players like Iker, Ander and especially Susaeta seem a bit labile to me.
Right now Valverde has no less than 37 players to choose from next season...current first team players, players returning from loan and players promoting from BA:
Óscar de Marcos - Xabi Etxeita - Aymeric Laporte - Mikel Balenziaga...