Positional sense, composure and agility/balance are usually more important for a full back than strength tbh, get yourself in the right position and the battle is 90% won, the average winger is hardly a battering ram.
I don't think we'll be as reliant on our full backs attacking abilities now with the inverted system and two out and out widemen so tbh it would be nice to get a younger version of Sagna on either side with maybe better passing, rather than signing 2 failed wingers with no positional sense.