I don't think it takes any special NDA protected knowledge to say that a new instance type was "worked on a for a while", given how rarely they release new inst

I don't think it takes any special NDA protected knowledge to say that a new instance type was "worked on a for a while", given how rarely they release new instance types (the i2 family was announced in Dec 2013). Likewise, the i* family is their "I/O intensive workload" family, so again, it's clear that gains in I/O performance was a goal when designing i3's, the i2 family was definitely showing its age, even compared to a modern laptop.