Voiceover mastering needs work...
Probably a known issue, but the female voiceovers for resource warnings really need to be re-equalized, and compressed/mastered to be understandable. Right now, they're extraordinarily bass-heavy and have almost no mid or high-range. Basically the opposite of what vocal tracks need when mixed with music and effects.
In addition to re-equalization, you might try "ducking" the music and FX channels when there's a voiceover happening. Basically turn the volume down on the rest of the game when an announcement is made.
On a somewhat related note, the "enemy is nearing (critical mass?)" announcement happens many, many times in a row. Don't know why, but I think one such announcement would be sufficient to notify me that I'm getting my ass handed to me.
Also, the "warning" for when a capital ship is nearing critical health is cool, but I usually can't find the unit it's talking about in time to do anything about it. I'm thinking some kind of indicator on the minimap where the ship in question is, or maybe an FPS-style damage direction indicator pointing toward the unit would be cool (kind of like how FA will show radar pings as arrows on the edge of the screen so you know what direction to look).