How to improve ranking of deep pages?

[CTSupp]

While this may sound like an obvious or stupid question at first...let me explain...

We are an e-commerce website which sells one type of item nationally; for sake of an example which is similar to us, you can think of an e-commerce site that sells movie theater tickets in cities and towns across the country. Our home page ranks very well for the appropriate keywords as well as some of our state and city pages rank very well for local searches.

However, while some state and city pages rank well for their respective local searches, others have a low page rank with some not even in the top 50 for their respective keywords.

My question is that we aren't clear why some pages will rank well while others wont when the competition looks similar for those local searches. And in today's Panda/Penguin era we are unsure of how to get more of these state/city pages ranking better?

For the record, we are quite strict about on-page SEO, 99% of our 5600 pages are crawled & we have minimum SEO errors from the SEOMoz crawls.

Can anyone provide some feedback & thoughts?

[CTSupp]

I find it really odd that a question like this has gotten no answers...is my question that difficult...or does no one have issues getting deep pages to rank well...or is my question really that silly?