It's true that since STR only adds 1:1 ATK is is less efficient for an archer to put points into STR. You can arguably get more benefit for your point by putting it into another stat. So long as you consider more than just damage to be important, there are more fruitful stats to put your points into. LUC giving crit rate, crit evasion, and ATK. DEX giving evasion and ATK. Basically, getting ATK from enchantments rather than STR is more efficient. It's expensive yes, but that's another issue. Technically speaking, the less stat points you put into STR, the more efficient use your points will be. HOWEVER, you need ATK as an archer so you have to get it somehow. That's why Rex is saying you need high enchant because that is one of the biggest things you can do to raise attack without needing to put into STR.
On the other hand you'll want to maximize your gear for stats as well so that is pretty much going to probably mean you'll need some STR lapis, which is fine. I'm not saying points into STR is bad, i'm saying that 1:1 ATK ratio is not good and LUC and DEX have other benefits not measurable by your ATK stat.
However, if the absolute only thing you care about is damage then STR will take a higher role, but only if you already have the appropriate DEX and LUC to ensure the most efficient accuracy and critical rates. But victory depends on a lot more than how much damage you do. Survivability in some form is required, don't forget that. DEX or HP. You have to do something or you're a one shot kill for any fighter/warrior.
Dipping down to 500 LUC for the sake of adding 100 STR would not be something I recommend in the least. You're not going to suddenly become a killing machine because you have 100 more ATK. But now with lower LUC, what happens when you miss a few more crits because your rate is too low? You start giving up a lot of potential damage because of that now. Also, that 100 LUC is giving you 30 ATK itself so you're looking to gain only 70 ATK which is at best is less than 150 damage on a dominant ele crit.
When comparing STR vs LUC with shooting attacks the STR is seriously inefficient for at least the first 600 points. STR does one thing, gives ATK, and at a poor ratio for shooting attacks. LUC gives crit rate, crit evasion, ATK, and critical damage (in this sense you double dip on the damage); much more efficient use of a point than STR. After 600 LUC you can debate between yourselves. I have the tendency to agree with Rex. If I was going to build for 60 UM PvP I would go with a high DEX, high HP, high LUC build, doing everything in my power to get my attack up by means other than STR (aside from the most efficient use of lapis slots). Some of the best opponents I fought when I played were random, not popularly known at the time, hunters who had added defensive measures. And even as a pure damage build I could not eat their HP before they ate mine. Very frustrating to consider yourself statistically superior yet continually getting killed.
EDIT: Also, regarding damage, since that's the only thing STR does. LUC adds .3 ATK per LUC. LUC also adds critical damage on a multiplier of 0 to 1.5, which is random. The average of that is .75 * LUC. So every point of LUC adds .3 ATK and .75 critical damage. 100 STR adds damage of 150 on a neutral element crit and 210 on a dominant element crit. 100 LUC adds damage of 120 on a neutral element crit and 138 on a dominant element crit. That's a difference of 30 on neutral eles and 72 in the absolute best case. There is simply no way it would be wise to toe the line of maximum crit rate by dropping down to 500 LUC. Even strictly in terms of damage it's not worth it, not to mention the other benefits that come with LUC. Remember, STR is nothing, NOTHING, more than an ATK raising stat, that's all it does. Yes, it does that one thing better than LUC (if you already have max crit rate) but it doesn't do it THAT much better. 1 STR adds 1.5 damage to a neutral element crit and 2.1 damage to a dominant ele crit. 1 LUC adds 1.2 damage to a neutral element crit and 1.38 damage to a dominant ele crit. Especially at neutral elements the difference between LUC and STR in terms of damage is pretty insignificant, even over the course of 600 stat points. And since STR does nothing more than add damage, it does so very inefficiently in comparison for shooting attacks.
So you're going to potentially start missing critical hits in order to get an extra double digit damage on your shots? Damage that is so low of an increase you won't even be able to discern it given the randomness of your LUC damage will cover it up. You literally won't see or feel yourself hitting any harder with 500 LUC 700 STR, but you risk dropping under 95% crit rate by doing so. If anything I would be looking to refine your build to lower your STR.
