I wonder if there was an element of 'let's play Lewis and we might be able to convince him to stay' involved, in which case it was just as 'development-focussed' as playing Sweet.
Young's mobility and marking is definitely ahead of Sweet, and Sweet probably also would have contributed 8 and 4 disposals - so I think at the end of the day it really doesn't matter. The finals Young played in, we still won.