Timmaigh: I also remember Pax Imperium: Eminent Domain. Best. Music. Ever. However, the planetary graphics, especially for bombardment, weren't that spectacular. For that, I have to give Imperium Galactica II top marks. Great soundtrack, and of course if you wanted to take a planet you didn't bombard it, you had to land your armor and take it. Or you could just land some armor and blow up a few buildings. Tragically, the developers of that game apparently didn't anticipate that Micro$oft would ever force an upgrade to a system beyond Windows 95/98/ME, and the game ceased to function thereafter.
I agree that turrets and shield facing would lead to micromanagment heck, especially in a game of this scale. Better to allow formations/maneuvers at the fleet scale and leave it at that.
Campaign games have always bothered me, because that's a synonym for "follow this story line, step-by-step, and if you survive here's where you'll wind up". Better to leave it up to the individual player, perhaps with modified victory conditions to incentivize them, and leave it at that.