You're thinking about it the wrong way. Hecarim's Q deals 16.6% more damage at rank 1. I don't care what kind of math you do it after that; it's dealing 16.6% more damage. His clear is faster.
Maybe a little. However, it was only ever up once on any given camp anyway, and you got to wait on the cooldown while you moved around between camps. Not really that concerned about this one.
Remember also that you're completely forgetting the fact that in anything before rank 3 of the ability, you're healing for more than before in every other situation, which definitely includes all the ganks you should be doing because... Well you're Hecarim. Let's be real. Fighting champions is like what that guy does.
You're referring to the "scraped" patch notes put up by fansites on the PBE? The ones that base their "patch notes" upon updates to the tooltips? We updated the tooltip because it was factually inaccurate.
Also, you're calling Spirit of Dread (Hecarim's W) his E. That kinda hurts your credibility man.
I say that purely as advice.