Just in case there is anyone affected by this, wanted to point this out. Our new requirements are basically that you need to have a DirectX11-capable card. On OSX and Linux, the equivalent is OpenGL 4.1.
On the three major lines of cards, this means: NVIDIA GTX 510+, Radeon HD5900+, or Intel HD4000+
This isn't because of any big fanciness in the graphics, but because of mesh instancing support on those cards. Basically it's a much more efficient way of using the GPU pipeline to draw a lot of little objects; and with thousands of ships onscreen at once here (in many cases 10s of thousands!) that's absolutely needed.
This had been the plan from the start, but unfortunately I had not realized that instancing support wasn't introduced until those cards.
For practical purposes, this means that the oldest Nvidia and AMD cards supported are from 2010 (8 years old!), and the oldest Intel onboard GPUs supported are from mid 2012 (Ivy Bridge and up -- still 6 years old!).
Thanks!