Todibo is only going to get better with playing time. He is seriously strong in one-on-ones and has great acceleration. Positioning needs work but that will come with playing time as he has his head in the game (unlike a Mina).
I still think a loan would be the best option as realistically, how much playing time will Valverde give him ahead of Pique, Umtiti and Lenglet?
It is a shame we don't have an experienced 4th CB option at a respectable price and have Todibo spend a year in LaLiga or a club like Watford who were interested.
BTW, how did Valencia manage to extract 12m from Sampdoria for Murillo. We would have sold him for a few million had we owned him.