Importance of rankings?
Rankings are important, but the most important aspect is the quality of information that you are going to provide on the web page. As Google says, build the website / webpages for users and not search-bots. A quality website with useful information will tend to drive more visitors, which in turn (the URLs) will be shared via social profiles of users, talked about and will lead to a returning visitor.
Favourite Ranking Strategies?
Originality, Uniqueness and Value (information) are the 3-major one's for content.
Elements to be covered in SEO site audit?
PageSpeed Insights, Mobile Friendliness & Website Validation.
Your Dream Feature not present in current SEO tools?
I think the mainstream SEO tools, nearly cover most of the aspects for the website optimization and usefulness. The things which I would feel will make the life simpler of the webmaster are:
a) to have an option to collectively compare the organic vs paid keywords at a go and
b) to figure out, all hidden keywords resulting in traffic, which further can be split into branded vs non-branded.