I have 3 Wordpress sites, all EMD, all following the same format but in 3 different niches but all music related.
Apart from the actual content (obviously they are different niches) they are identical. Same plugins, same amount and type of SEO ( I know this because I did all 3 sites in sequence).
All the sites are informative and contain original content. Nothing spun or copied from other sources. All written by me.
2 of the sites have maintained page 1 status. The other has been knocked into oblivion. It's still in the SERPs but was page 1 and is now not even top 50.
I'd suggest this adds an element of luck into the process of ranking a niche website.