If we're talking about the same thing then I think casting stones just because it is based on MySQL is severely misguided. MySQL has decades of optimizations and this particular system at Amazon has solved scaling problems and brought reliability to countless services without ever being the direct cause of an outage (to the best of my knowledge).

Indeed, MySQL is not without its flaws but many of these are related to its quirks in transactions and replication which this system completely solves. The cherry on top is that you have a rock solid database with a familiar querying language and a massive knowledge base to get help from when needed. Oh, and did I mention this system supports multiple storage engines besides just MySQL/InnoDB?

I for one wish we would open source this system though there are a ton of hurdles both technical and not. I think it would do wonders for the greater tech community by providing a much better option as your needs grow beyond a single node system. It has certainly served Amazon well in that role and I've heard Facebook and YouTube have similar systems based on MySQL.

To further address your comment about Amazon/AWS lacking quality: this system is the epitome of our values of pragmatism and focusing our efforts on innovating where we can make the biggest impact. Hand rolling your own storage engines is fun and all but countless others have already spent decades doing so for marginal gains.