He stated, and the rest of the ls that was awake at this time who totally backed him up, that full on STR build for these WS would be much better dmg output than dex.
This is false. Instead of going into the math too deeply however I'm just going to give the focal points on why. Secondary Mods vs fSTR (base damage calculation)
-- for every 4 strength you raise base damage by one up until the cap at which point strength won't give you any more damage aside from 2 str == 1 attack. DE and Evisc both have a 30% dex mod meaning for every 4 dex you get 1.2 wsc which is multiplied by alpha value, roughly resulting in 4 dex == 1 base damage. Summary:
4 strength raises base damage by 1 but caps relatively fast on daggers. 4 dex will also raise base damage by 1 but has no cap, and also affects evisceration's criticals. Roughly speaking
1 dex == 1 strength, but dex does not cap whereas strength does.
This is important. The dex mod of sneak attack has no cap and is 4 times more beneficial. Whereas you need 4 str to raise base damage by 1 when you use sneak attack it's a 1 to 1 ratio. This 1 dex == 1 base damage
1 dex is worth 4 points of strength, making dexterity four times more important than strength when you stack sneak attack.
This rule is not 100% foolproof but rather 98% and the law to go by. 2 strength raises attack by 1 and 3 attack is ~~~ 1% average pDIF increase so that will affect the final result, but it will be so minuscule that it won't have any bearing on the final verdict.
Final Summary: If you are performing a weaponskill or using sneak attack a thief gets more benefit from dexterity than they do from strength. Thief is a unique class, and the only job this rule applies to
other melee job will get more benefit from strength than dex regardless of what they're doing, and I have a strong hunch your linkshell leader has never played thief. While it's true that str >>> dex for war, monk, drk, etc, this role is reversed on thief, and this is one of the little intricacies that makes the job so fascinating to me. I'm a little dex/crit whore, and I have enough dex/crit power that I can rival and outdo most other players on their various jobs.
One final thought. Don't ignore
strength and attack. While I don't recommend gearing for strength before dex, I DO recommend using it where you can. There are a lot of pieces that incorporate both strength AND dex (hecatomb), and our raider's armlets has the whole kit and kaboodle (str, dex, accuracy, attack), while some armor slots don't have any awesome dex choices but great attack choices (the back has some great attack options). If you follow the basic rule that 1 point of dex is better than 1 point of str, but get as much of everything as you can you'll do just fine.