Overall I would say most depends on WordPress itself. If Matt Cutts says so, it should be truth. See slide #12 where he says that WP takes care of 80-90 % of seo issues.
http://www.mattcutts.com/blog/seo-for-bloggers/
That means we should take care of remaining 10-20%. By integrating Schema.org into Tiny Forge I would guess we would add 1-5%, also titles are generated automatically and the rest you have to add with SEO plugin:
http://wordpress.org/plugins/wordpress-seo/
Remember, that content is the king, if articles are not good, SEO will do nothing. Also page load speed affects SEO, that means you would like to use caching plugin and/or CDN (Content Delivery Network).
http://wordpress.org/plugins/w3-total-cache/
https://www.cloudflare.com
