Just a robots.txt file template which is suitable for WPEngine use

robots.txt

# All Agents
User-agent: *
Disallow: /blogs.dir
Disallow: /cgi-bin
Disallow: /wp-content/cache
Disallow: /wp-content/languages
Disallow: /wp-content/mu-plugins
Disallow: /wp-content/plugins
Disallow: /wp-content/upgrade
Disallow: /wp-admin
Disallow: /wp-includes
Disallow: /_wpeprivate
Disallow: /trackback
Disallow: */trackback
Disallow: /*?*
Disallow: /*?

# Google Image
User-agent: Googlebot-Image
Allow: /*
Disallow: /cgi-bin
Disallow: /wp-admin
Disallow: /wp-includes
Disallow: /trackback
Disallow: /comments

# Google AdSense
User-agent: Mediapartners-Google*
Disallow:
Allow: /*

# Internet Archiver Wayback Machine
User-agent: ia_archiver
Disallow: /
 
# digg mirror
User-agent: duggmirror
Disallow: /

Sitemap: www.yourdomain.com/yoursitemap.xml