Would a Lion-class battleship beside Hood have changed the battle with Bismarck?
Short answerYes; nine reliable 16-inch guns would provide substantially more effective fire and could prevent Bismarck's escape.
NotesThe buildable Lion design carried nine 16-inch guns in three triple turrets, avoiding the reliability problems of Prince of Wales's quadruple mountings. Its greater and more dependable weight of fire makes Bismarck's escape doubtful in this counterfactual. The difference is not only shell caliber: a Lion able to keep its turrets operating would sustain pressure that Prince of Wales could not. Nominal broadside figures matter less than the combat value of mountings that keep working.