It’s true that some usages of the subjunctive mood are gradually disappearing. But that does not mean we should drop all usages; some are required for clarity. Consider the three examples below; each contains an indicative noun (shown in red type) that should have been a subjunctive:
To maintain all previous Google ranking data for the domain, it is advisable that a buyer grabs the domain before it is “dropped”. (Source)
After he reads “it is advisable that,” the reader expects to see a subjunctive. When he sees the indicative “grabs,” he probably guesses the meaning of the sentence anyway and recognizes that the writer does not know enough grammar to use the subjunctive “grab” here.
We hereby ask that gun licensing laws are reviewed with immediate effect to allow designated people in the Jewish communities and institutions to own weapons for the essential protection of their communities, as well as receiving the necessary training to protect their members from potential terror attacks.” (Source)
After he reads “we hereby ask,” the reader expects to see a subjunctive. When he sees the indicative “are reviewed,” he probably guesses the meaning of the sentence anyway and recognizes that the writer does not know enough grammar to use the subjunctive “be reviewed” here.
Now, I think it is important that sex is consensual. (Source)
After he reads “it is important that,” the reader expects to see either an indicative or a subjunctive, depending on the writer’s meaning. When he sees the indicative “is,” he assumes it is correct. That is, he assumes the writer means that it is a good thing that sex is always consensual.
But then the reader thinks, “Wait, I know sex is not always consensual; that’s why we have laws against rape. Why doesn’t this writer know that?” Then he rereads the sentence and recognizes that the writer meant that sex always should be consensual but did not know enough grammar to have used the subjunctive “be” here.
The Takeaway: If you habitually use the indicative where the logic of the sentence calls for the subjunctive, intelligent readers will recognize that you did not learn all your grammar. And in some cases, as in the third example above, your reader may become confused and irritated. If you did not learn the subjunctive mood, study it now.