The steam ships comparison (especially between paddle steamers and screw blockships) seemed the most apt, though the conversion from coal burners to oil burners is also a good starting point, since the Excelsior seems as akin to the oil burning battleships vs. the coal burning pre-Dreadnoughts when you compare her to her immediate predecessor (Enterprise-class)
If we go by the wooden ship era comparison, Constellation seems akin to the warship conversions or limited ironclads like the French Gloire which turned wooden hulled ships into iron-clad screw-steamers, while Excelsior is more akin to HMS Warrior, built from scratch and completely abandoning wooden hulls at all.
Barbettes vs. Turrets vs. Broadside armaments are another interesting example of comparisons. (If anyone's interested in more detail on this btw, I highly highly recommend the Conway's History of the Ship volume Steel, Steam and Shellfire