Thanks for joining the conversation, Benjamin; and for the highly detailed post. It is ... nice to meet you.
In all honesty, though, I can't say that is it particularly confidence inspiring.
Lots of platforms are "constantly growing and evolving". I guess I can faintly remember the days that eBay had horrendous outages ... and GMail, and probably a few other giants.
But that is the biggest concern of all. You see, the current rate of SmartThings growth is trivial compared to your goals; a couple hundred thousand hubs currently growing at, what, a few thousand a month; compared to a couple million hubs (growing exponentially) as Samsung UHD TVs come online and as marketing efforts suddenly reach critical mass and cause another "hockey-stick" of growth?
Your post did mention proactive risk management initiatives, and I appreciate your inclusion of them. I hope you and your team -- and the entire company -- follows through. Thanks!