Form and rules
How it works
Wish/if only + past simple expresses an unreal present situation; + past perfect expresses past regret.
Wish + would can criticize repeated behavior or request a change outside the speaker's direct control.
Would rather + base verb expresses your own preference; would rather + different subject + past form expresses a preference about another person's action.
It's time + subject + past simple means an action should already happen; It's time to + infinitive is more neutral.
Could after wish/if only can express desired ability or possibility.