Better representation, obviously. This is like asking the advantage of increasing the number of pixels on a screen.
How many average constituents per member is right? We're not going back to <50k constituents per member like the U.S. in the 1790s or Nordic countries today, but unclear why we can't get under 300k per constituent like Mexico or Australia.
We're an extreme outlier in OECD countries:
https://www.amacad.org/ourcommonpurpose/enlarging-the-house/...
Looking at federations instead of unitary states, Mexico has ~250k per member, about 3x better than the U.S., while Australia has under 200k per member. Germany has only a little over 100k per member.
Potential effects of better U.S. representation here: https://thirty-thousand.org
> On the other hand it's about on par with the EU parliament.
The EU is a voluntary economic union (see Brexit), the U.S. is a federation of states which may not unilaterally secede (see Texas v. White).
