+1 to FAKEASNEVER and WARWAS.
Perhaps C.
I say that there should be crystals given out for each time you defeat the highest infestation on your radar. Not too much, just a little incentive for commanders to complete higher infestation levels.
Perhaps the amount of crystals should go in hand with the infestation level. A level 1 gives 10 crystals, a level 8 gives 80, a level 32 gives 320, and so on.
For example, if my highest infest level is a 41 Defensive infest, but I have a level 40 Offensive infest, If I defend the lvl 41, I get a few crystals, but if I attack the lvl 40 Offensive infest, even though it IS my highest OFFENSIVE infest, it was not the highest on my radar, and I get a normal pay out (or lack of one :p)
This would help keep players moving up in infest levels.
Also, there ought to be a 'big' reward after reaching the lvl 160 infestation. Perhaps 10,000 crystals instead of the 'usual' 1600 you might get. And maybe even one for reaching the 'midpoint' ie. your first successful lvl 80 infest attack/defend gives 5k crystals instead of 800
I don't know. The idea might need balancing. I shall see if anyone else chimes in on this.
But whatever you do, don't give crystals for EVERY infest you attack. That helps no one in the long run.
And leave the infest mechanics as-is! Please!