*WARNING LONG POST!*
There is a slight problem in the game at the moment for catering to the SP and the MP audience.
The main issue is that games last too long for MP, with slow starts and costly upgrades/ships.
I think for most players the SP is ok, I am quite happy to play the game at that pace in SP, because I can save at any point.
However, in MP, most players would like to see a 90min game for 1v1 and 2v2.
Some suggestions have been to create options to speed up resource rates. However, I feel that these are artificial aids that merely patch up intrinsic flaws in the games current economy modelling. I don't feel that although I will persevere in a SP game with longer resource gathering times, it doesn't mean they are correct. A SP player skirmish should play as fast as the MP, without simple measures such as doubling resources.
I believe that economic model at the moment needs to be completely reworked. This game works on a fairly flat economic growth, even after 90mins of playing on a tiny map, you will likely have only doubled your credit economy. This just doesn't fit with what you would expect from an expansionist strategy game. Capturing planets from an economic standpoint is not that beneficial (there are other benefits such as fleet cap, and increased research, however these only serve to further the length of the game as you don't have the economy to utilise it).
To illustrate the point, I will use the capital planet infrastructure upgrade. If you look at the population increase you gain, that translates to roughly 1/sec credit increase in income on base credit generation. It takes roughly 4 population increase to generate .1/sec credit increase. The upgrade costs 750 credits, meaning that it will take at least 15 minutes for you to recoup your investment.
The figures are even bleaker for Trade outposts, given that you have to pay for the civic research stations and then 1000 credits for each outpost and will likely only receive ~400 credits every run, which could take up to 5 mins, meaning that it will take you around ~30mins to recoup on the investment.
The economic model in this game needs to address how credits are generated, metal and crystal do not suffer the same issues, as asteroids are only moderately affected by allegiance and always have the same transfer rates. This would create the biggest imbalance in simply introducing a double resource option. Metal and Crystal mining would be the primary source of income and doubling their rates would mean that there would no longer be any real strategy to credit income gathering. Balance would be thrown out of the window for research trees and fleet building. The main skill would come down to who could sell on the black market quickest.
Basic balance suggestions I would like to see considered are:-
Slightly increasing base planetary credit income for non-capital planets. The main reason for colonisation should be credit income generation. Asteroids should remain at 0.
Increasing population credit income generation so 4 population is now .3 credits/sec. To encourage investment in economic growth.
Reducing trade setup costs and making them available early, so they are an option.
Advanced suggestions
Make ship wreckage salvagable so that can be a source of income for aggressive players and nice early bonus for killing those native ships.
Allow taxation rates to be manipulated, maybe at expense of planet growth/allegiance.
Later techs could have costs increased so that the game still can maintain length in SP and certain MP games.
Essentially the major hinderance to growth is that economic credit growth is fairly stagnant, whereas the cost of everything is exponential. Credit income has to be balanced and short term patches like double resources will not solve the original problem but likely cause others.