Well in my opinion it's Charisma, it depends though what kind of usage is the commander for. If it's used to idle in base then of course Financier, Efficiency, Ingenuity are a bit better but Charisma does bring more actions as well, so Charisma is good for battles because it largens the amount of ships you can have, and it's good also for idling in the base because you get more actions.
Charisma is far supirior to anything else more ships in combat is more firepower and you have more actions in colonys
Efficency is bad. The resource collection bonus is point less becouse resource buildings give to little of income at higer lvls of building for upgrade costs compered to resource node.Fuel use reduction is nice in theory but 1/4 reduction for points spend isnt good. 50 points give 25% less fuel cost but 50 points are better spend in Carisma or Tactics.
Ingenuity its usefull for goods production and ship building but dont know if its better in the long run vs Carisma and Tactics.
Tactics 2nd best state. The ships you can use do more damage but is using more ships much better ?
FInancier in the long run not much of use after you have reserched everything you dont need it.
Charisma is the definite 'must-have' stat.
Efficiency, no need for this one given colony resource generation is so poor at the moment, the fuel use is neglible
Ingenuity, a good stat to have. Would not choose to pump up over charisma (for my more combat commander) or Financier (for my base leaders).
Tactics, potentially a good stat to have, but why choose this over Charisma for a non-base leader?
Just remember guys, despite Charisma being fantastic in a lot of situations, no attribute can excel in a vacuum. Dozens of ships may seem daunting, but a handful of well upgraded and supported vessels can punch a hole in a sizable armada of weaker ones!
Better equipment, better ships, and a stronger economy win out in the long run.
"Never interrupt your enemy when he is making a mistake."
Napoleon Bonaparte (1769 - 1821)
I would suggest tweak efficiency to be three (maybe four) times more powerful than it currently is. It would then be a significant fuel saving for deployed fleets, and give mines, farms and drilling a much need boost so there would actually be a point in using those buildings.
A little expanded on part of charisma - it increases your colony queue with REALLY helps early game and with production later on. I haven't played long enough on this account (the other is Gobyon) to really know what's best, but I'm casting my vote on what I think is best for early game, and that is charisma.