Liam Fox is right of course although I doubt that he will be happy that the letter leaked because the leak weakens his position.
We need some proper strategic thinking to serve as the foundation of the review and, in my view, we have seen very little of that. Defence capabilities need to be fit for the conflicts of the 2040s and these, it seems to me, will be over access to resources more than they will be about anything else. Command of maritime trade routes will be the single most important capability for an island nation that can't feed itself. The UK scarcely needs a standing army at all, which is why I think the Army has been careful to get itself properly mired in Afghanistan - it's all a question of survival.