a beer doesn't have to be strong to barrel age. I will say that after 50 years and the number of batches that have likely gone through it I wouldn't expect there to be any oak character left to speak of. the main flavor benefit will be from the wine that was in it last and the micro oxidation that occurs as o2 permeates through the wood. So I'd stay away from hoppy beers. I like the Saison idea though.