The big one – relatively speaking, of course – in my mind is the site to site transporting.
In “Day of the Dove”, Kirk asks Spock, ”Intra-ship beaming, is it possible?” and Spock rattled off a litany of reasons why it was considered too dangerous in all but the most necessary circumstances.
However, we see in Disco, starting with “Context is for Kings”, that they can just order the computer to transport them from one room of the ship to another without hesitation.
It’s a minor quibble all things considered. And clearly something most of the Disco detractors aren’t even aware of.