Could the Imperial German Navy have foreseen that Blücher would be outclassed?
Short answerPartly; Blücher was an understandable early misstep, but post-1905 cruiser designs should increasingly have followed the all-big-gun logic already reshaping battleships.
NotesA navy already adopting an all-big-gun battleship had reason to question why a new cruiser retained a mixed heavy battery. Germany receives some allowance because Blücher came from an early stage in its emergence as a major naval power and before battlecruiser information was fully understood. That excuse weakens rapidly after 1905, when fire control, logistics, and the Dreadnought model all pointed toward gun standardisation. Later designs such as the British Minotaur class are harder to defend because the Royal Navy was already producing battlecruisers.