I've been thinking about this a lot, ever since the launch of Elemental. It seemed to me like much of the design felt like things that belonged in GalCiv. It makes sense, since GalCiv was the only strategy game Stardock had as a reference. Generally, on the gameplay end, it's been the fantasy stuff that didn't work (so far)
Trying to refire up GalCiv II, but Impulse account has a corrupt GCII serial (I sent that in to support, I found my old serial on my 10 yr old laptop so that solves it for now)- so going on memory.
Colony Rush- I'm fine with this mechanic. It makes sense.
Planet building- here's an area where the Elemental approach would work better, especially after 1.1. The all-labs/all-factories approach was rather lame, and the Elemental system is a vast improvement. Modifiers: Population would be a planetary resource, and planets would have to be self-sufficient on food. Population would also determine planet level. (This would also solve people not wanting to research farming). The morale/taxation mechanic would remain. Focusing labs/military/social is fine, but the sliders do need to go (Brad agrees with this looking at his things he wished to change list)
Bonus resources/starbases. This is something that needs a revamp. I'd suggest that mining craft mine the bonus resources, if a mining resource is in neutral space, multiple races can harvest it.
Economic Starbases were gamey, and I think Starbases should mostly be military. Influence modules should be allowed in military starbases. Starbases should exert a ZOC if strong enough.
Trade- works well. Just not with trade starbases
Anomalies- worked fine. Need space monsters from GCI back
Research- seperating research by color, with unique trees- sounds potentially interesting. Research cost should be based on the last tech chosen, for the sake of balance. Major breakthroughs could be handled by the rare tech mechanic.
Alignment and lore- Alignment needs a revamp. Kael would be a nice asset here. Kael would also be a nice asset on the lore, but the lore in GCII is massively better then in Elemental. Twilight helped significantly here, so there's hope for Elemental in the future.
Military Mechanics- I'd like to see commanders added. I think the mechanic works well, but needs expansion, and possibly racially unique weapons. Planetary invasion mechanics need somewwhat of a rework also. I would like to see limited, optional tactical battles- but only if Stardock can do them right- so far Elemental hasn't shown that.
Events- events were good. Mega Events were a little too imbalancing. This is an area Kael could help, his events in FFHII were better.
Special Abilities- need a little more balance to them. I turned them off due to them being so imbalanced.
AI and multiplayer: AI for a space game is a hell of a lot easier then AI for a fantasy game. A lot of the AI problems in Elemental are primarily game balance problems from a much more multidimensional game then a Space Civilization game. I can't think of any strategy game with good AI since Fantasy General. Multiplayer is a necessity, and that would require some gameplay tweaks as well. The AI is more important though, as most people never play multi.
I know this is more of a GalCiv thread, but some of this may help Elemental, by pointing out the good in GalCiv II that could or could not apply to Elemental in the future.