I just picked up GalCiv and I'm really impressed. Gameplay is excellent, the events are interesting and as advertised, the AI kicks ass and takes names. That being said, I would love to see some ship design capability and a more-involved combat model.
I was/am a huge fan of MOO2 (avoided MOO3 based on what I heard), despite some of its balance problems and some of the weaknesses with the AI. Space combat in MOO2 could be dramatic and intense. And ship design was probably my favorite part of that game, producing the next generation of ship, and equipping them with specific armaments for specific tasks (especially the funky weapons like inertial destabilizers). Combining the strengths of MOO2 to the strengths of GalCiv, if done well, would to me, at least, result in the perfect game.
Of course, I realize that you can't just drop MOO2's tactical game into GalCiv (pretty much a mini-game within the main game). And the more generalized nature of ships pretty much prohibits a verbatim copy of the MOO2 ship design feature. Not to mention the code, art and testing required to add such extensive new features.
However, despite these challenges, I do believe that well-throughout design and combat improvements are possible for GalCiv. I don't want an inappropriate level of detail (say what is found in the rpg Traveler), calculating weapon arcs, hull volumes and power output ratings of reactors. Instead, I want to adjust what is already there. Alpha Centauri, while having a similar combat system to GalCiv, was able to provide a decent unit design feature. In GalCiv, a similar ship design screen could allow players to design ships, including any or all of the following:
a) choosing a picture for the ship

choosing a name for the ship design
c) adjusting the attack/defense/movement ratings for the ship, increasing/decreasing the cost accordingly (rather than deal with specific weapons and arcs, you could deal with things in more general batteries)
d) add special features to specific ship classes. For example, you could produce an 'Aegis' ship that adds to the defense ratings of the stack. Or you could add a targeting computer that adds +1 to the attack roll (but not over the maximum attack rating). Or you could add 'stealth' which reduces the range that a ship can be detected at.
e) weapon ranges - you don't need a tactical map to do weapon ranges. Rather, weapon ranges could translate into an initiative system, so that longer ranges can result in a 'first strike capability'.
f) defining weapon and defense classes. Each ship would have at least weapon class (laser, missile, particle. etc), and for an additional cost could purchase extra class types. Having different weapons and defenses, though costly provides flexibility versus different foes. So a ship could have an attack of 6 (laser, missile) indicating that it has both laser and missile weapons. Defenses also can have classes (armor, jammers, point defense laser, shields). These classes have different properties. For example, lasers might do less damage (-1 hp), but have few effective countermeasures. Missiles might do more damage (+1 hp), but a ship with jammers gets +2 to defense.
Enhanced ship combat could involve the following:
a) allowing each ship in a stack to choose its target in a defending stack, especially if some of the ship design features discussed above are implemented

selecting a role for each ship. For example a ship set to 'harry' increases its defense but lowers its potential damage as it refuses to engage closely. Conversely, a ship set to 'assault' increases its attack, but lowers its defense due to its aggressive stance.
c) allow ships in a stack to aid each other, so that task force creation becomes important
d) be a strictly optional system - I don't want to bother every time two scouts run into each other. But I do care when the Drengin fleet tries to sack Earth.
Of course, it's still a lot of work to design, code and test. Still, I hope that the designers consider that many gamers enjoy combat and ship design. And I don't think that saying play Moo2 or Space Empires IV is the answer, because we also enjoy all the strengths that GalCiv already has. Good game design means that it doesn't have to be an either/or decision. I'm sure such added functionality would only increase sales for the game and its ultimate longevity. We don't want Starcraft or Homeworld action and clickfests. We want to manage our fights with the same care that we manage our colonies.