Hello and Welcome,
This topic has been discussed here many times.
The criteria is the same for everyone.
I would class my location as semi rural, if rural gets a change of criteria then what about semi rural, then what about those slightly above semi rural but not quite urban. This is going to get messy very quickly.
Have you read the following post that gives tips for rural players…
I see many rural areas that are way more populated than where I am.
The people reviewing should be relatively local. yes, depending on your location it may slip in to a neighbouring country especially when Upgrades get used.
As long as reviewers use the same criteria for all nominations then there should be no issues.
If you have had problems with specific nominations then post them and people will discuss if they have been correctly rejected or whether improvements could be made to improve your chances.
Good luck.