Combat not taking movement point?

I concur.  If intention is to allow multiple attack per turn, perhaps the cost of each battle (in movement) might be increased.  This will force both attackers and defenders to balance between large stacks and skirmish lines. 

Multiple attacks per turn have been in for a while, I'm just pretty sure in Gal Civ 2 they did cost a movement point each, so that you could do skirmish lines, like you say.  it does add to strategy, I could see a desperate attempt to get a transport past a tougher enemy fleet involving some very interesting set ups...  but only if the attacks cost movement.