I just realized the skill bonus you get from stats in GH2 is different from GH1.
In GH1 its: (attribute + 2)/3
In GH2 its (attribute +1)/2
So in GH1 you want numbers like 1, 4, 7, 10, 13, 16, etc.
Yet in GH2 you just want an odd number - so 10 gives the same bonus as 9.
Although it varies based on the application. Charm affects the reaction modifier for every single point you add to it. Ego gives you 1 point of free cyberware trauma for every 4 points. Knowledge gives an extra skill slot for every 5 points.
I also notice that, even though you only have one skill, you still use perception on ranged weapons over DC10 and missiles. You also use body stat for unarmed attacks and on melee weapons over DC10, so if you're going to use a big melee weapon - even in a mecha - you need a good body stat.
It also looks like Knowledge is used for the salvage rolls along with repair, even though I always thought Craft was always used with repair. Weird. Craft seems to be used for regular repair rolls though. And Spot Weakness doesn't seem to add any stat, it just takes your skill value in it.
All the stats are really useful though. Reflexes is needed for mecha piloting and guns DC10 or below; speed is needed for initiative, blocking with shields, and personal scale dodging (or acrobatics in mecha scale if you have the talent and a reflex system); perception is needed for sight radius, missiles, and DC10+ ranged weapons; body is needed for personal scale HP, unarmed melee, and melee over DC10; craft is needed for electronic warfare; ego is needed for cyberware and intimidation rolls; knowledge is needed for salvage rolls, mecha engineering, and total skill slots; and charm is needed for the reaction modifier, getting rumors, and general conversation/shopping/performance.
Plus with the way you only get 20 stat points total instead of 9 or so in every stat (GH1), it really makes the stat system more complex and meaningful.
I'm really liking the GH2 mechanics so far. I'm curious to see what all he changes with his next update, I seem to recall reading about major balance changes.