Considering this, I wonder why the choice of Quake 2 instead of Quake 1 since the main thing Quake 2 introduced has over Quake 1 was colored lighting but that was only available in the OpenGL version.
The MD2 model format is considerably extended over MDL, in size limits, vertex resolution, and features like texture animations. And while Q1 had the split between Netquake and Quakeworld networking, Q2 has a single system. Those kinds of refinements can make the difference.