The Indicative mood is only used in declarative sentences, while the others are used in questions and commands.

The Indicative mood has only two-member opposemes, while the others have three-member opposemes.

The Indicative mood reflects the relation of the action to the speaker's object, while the others reflect the relation to the subject.

The Indicative mood presents the action as taking place in reality, while the other moods represent the action not as real, but as desired or imagined, thus discarding the notion of real time/tense.