London currently has 73 MPs out of 650 (11.2%) when they have 9mil out of 67million people (13.2%).
So guess you're right that they'd get stronger representation.
However on the other hand, people like the Green party got 2.7% of the vote in 2019 while only getting 0.15% of the seats.
Some voices get stronger, but it's not just cities.
I think the Internet is partially to blame.
The negative stuff happening in the world seems to spread so much faster and get so much more publicity that it's easy to end up in a constant negative spiral