MK was, without question, the better designed park. Made by the same WED designers who gave us New Orleans Square and the World's Fair exhibits, it benefitted from over a decade of Disneyland operating experience and a much more substantial budget to work with. Many attractions were made longer and/or with more detail and the new exclusive stuff (CBJ, HoP, MMR, SM) made extensive use of the latest tech WED could get their hands on. MK of the mid-to-late 70s was easily better than its West Coast counterpart, and arguably remained so until the early 1990s.
The difference now is that many of the design and operating practices that were put in place at opening have been removed or neglected over time. This doesn't just include rides like 20K or Toad, but architectural features like the Tomorrowland towers, the Fantasyland Skyway chalet and hillside, the original hub, pavement details (now just flat, plain red), unique shops, barker brids, counter service restaurants that served food on real plates with cuttlery (they still have the dishwahers apparently), more frequently updated daytime parades, the Saloon Revue, Tom Sawyer Island's spinning and teeter-totter rocks, the Fife & Drum corps, Tomorrowland stage shows, park benches, West Centre Street, restaurant menus in binders (like King Stefan's used to have), breakfast at Tony's...the list goes on.
DLR simply does a better job at "plussing" their rides and keeping them in good working order, which gives the impression of a better experience than their MK counterparts, even if the latter's versions are longer (Jungle Cruise, Peter Pan) or better laid out (Small World, Space Mountain).