I wish Google would publish their ranking algorithm so people wouldn't have to guess as to how much of a hit they were taking if their site wasn't perfectly optimized or designed. Most everyone is on mobile-friendly layouts anyway but I would love to demystify and disempower "SEO Experts" and just have improvements to improve search be less subjective / random feeling. Run a tool, get a score, make improvements and then focus on getting organic shares / links. Simple.