Performance and SEO - Looping through one template file versus separate templates

Kinda curious about the performance / optimization achieved or lost when a decision is made to develop a page to loop back through itself versus breaking them apart into separate templates?

I know that people have gotten pretty creative with EE since you can’t nest a template group inside of another, but what about in terms of performance or even SEO?

For example if you had www.domain.com/news-title as a standalone entry page which was in fact part of the index page versus something like www.domain.com/news/news-title which would be the index.php file inside of a group called ‘news’.

I was wondering what the best practices were in regards to performance and also SEO since I’ve also read that url’s and page titles are ranked heavier towards the left as loose weight as you move towards the right. If this is the case, then one would expect a more specific URL such as www.domain.com/news-title would be more successful than a slightly more generic URL such as www.domain.com/news/news-title.

Am I incorrect on my thinking here? How would one method impact performance versus the other on a high traffic website (5+ million views per month)?

Thanks