I like Romulans. Sue me.
Balance of Terror is good because of the drama, the tension between Kirk and the Commander, Styles and Spock. It also mimics to a "T" a submarine movie and so demonstrates that Trek is as much about characters and drama as the space opera setting.
And this is by design. Star Trek is a multi-modal platform that can tell multiple types of stories and dramas and comedies within that sandbox. That some don't appeal to you, or to me, is a feature, not a bug.
It doesn't make less Star Trek, it doesn't mean the writers hate the genre, and it doesn't damage the brand.
Never seen it. Don't care to.
Also, Star Trek is all made up so it can make up drama, romance, comedy, interpersonal difficulties. It is not history, nor a period piecd.