There should be a public survey which rates their journey experience.
Londoners have different experiences using different tube lines.
Using an online public poll/social media we can see what Londoners think of their commute. What is good and what is bad about their journey and the feedback can be used to improve the system.
The feedback can be used to improve the least favorable tube lines, so that they are more utilised, putting less pressure on other tube lines.
Why doesn't the tfl have an official app for oyster top or live tube information?