My main gripe would be the voice overs. They got Christie and Distephano's actors to reprise them, and then only used them for grunts and moans when taking damage.
Only Father's vo was used right.
I didn't like the lack of blue aliens either, I think I remember testing the damage out on them and they packed a slight more offensive capability than the drones did knocking your health bar dow but variety is the spice of life.