I think that in the past, the people in charge made a greater effort to portray Starfleet as a realistic, well-structured organization. There were occasional hiccups, of course, but overall there was a sense of oversight and internal logic. Nowadays, it often feels more casual—almost as if anything can happen simply because someone thinks it’s a cool idea, without much regard for consistency.
For example: “I’m a fan of Halloween, so let’s slap NCC-1031 on the hero ship.” Or, “I love the 23rd-century Shangri-La design, so let’s bring it into the 24th century mostly unchanged.” Then it’s described as a refit of the Titan, and on top of that, it’s given one of the most prestigious names in Starfleet—despite being described as a mediocre rust bucket. Heck, Strange New Worlds is now in its third season, yet the rank stripes of the main characters still haven’t been corrected.