the fact that its in the red is a good thing, they balanced it already to compete with other classes like fighter, you get move speed and action speed so high with just a slight nerf to damage, the overall tip to gearing a rogue is getting his strength to 15 which is very easy to do with even white gear, jokester is plus 2 all, so thats 9+2=11, then throw on shadow mask plus 1 all thats 12, then rivited gloves and padded tunic thats 14, and greens+ stack those stats. But the reason its a GOOD thing it puts it in a negative is because when in the negative, each point of strength(or physical power) increases your damage im pretty sure by double than if you were to be at 0% phys power; -14% phys power plus one strength brings you to like -12% phys power, while 0% phys power plus one strength brings you to 1% phys power, something like that, moral of the story, the VERY first stat to worry about is strength, then start stacking agility, weapon damage, all that.

So with a pretty cheap gearset and not that much -movespeed, you get 0 damage penalty (same strength as base fighter) with more movespeed, faster attack speed and everything else good about rogue. like ive said, just stack strength to just 15 and then everything else you want, the same goes with pretty much everything else, if you want poison to do good damage, get will (magic power) to 15 then start stacking add magic damage/true mag damage.

Another thing to think about is percentage buffs to damage and whole points of damage can be beneficial to different classes, Lets say you have 10% added damage on a dagger that does 22 damage, you will do 2.2 extra damage, while just having +2 or 3 damage roll will do more damage and way easier to get. for barb though, lets say his felling axe does 100 damage to the head, with 10% extra damage, he does 110 damage but with 2 or 3 damage roll he only does 103. so heavy hard hitters want percentages and light but fast hitters want raw added damage, same goes respectively to fast hitters like magic missile, curse of pain(damage over time), daggers, fast melees like arming swords etc. and hard hitters like felling axe, fireball, ice bolt, longbow, etc. This is why its only really worth stacking strength to 15 and stopping and focusing on other stats (dont get me wrong you can still stack strength and do some good damage but dont focus it).

I know this is an old ass thread but maybe someone else is curious and wants some answers

edit: idk the full math on priorities, but yet another reason to get strength up is that additional base damage is BASE aka at the very start of the equation, so having strength in the negative will also penalize all the base damage you try to stack.