Reputation and Nb of followers won't cut it for sure. The number of page views also has its issues. As you said, this number only includes the page views on Steemit. To palliate, this number could be coded in the blockchain to increment everytime a post content is fetched. But then, it would be really to cheat the system, with a big of programming skills.

The best proposal regarding a metrics was done by @scipio a few months ago: UAJS.

I actually worked a bit on developing this idea but it was too much work.