should i go low dex thief?

Given that you're an assassin, you'll eventually need to be able to equip at least a Red Craven, which has a requirement of 140 DEX by level 100:


Assuming you have mediocre gear by around that level: You should be able to get ~30 DEX from a scrolled Zak Helm, ~5 DEX from a MoN, ~30-40 DEX from other equips (Rat Mouth, LPQ Glasses or Spec Goggles, earrings, bottom, shoes), + a little more from event equips.

You could suffice with about ~65 base DEX by level 100 if you have the above. If you can't afford gear, you should definitely go higher, then eventually wash out the extra points when you do acquire it.

 

DEX-less claws are limited by weapon attack cap, and the highest clean weapon attack claw which requires 0 DEX is Night Raven's Claw (NRC), at lv 90.

The best clean NRC has 44wa, and a perfect NRC +7 will only be 79wa.
However, if you get better DEX, you open yourself for the highest weapon attack claws such as Cravens, Dragon sleve, Speargraves and the final end-game claw, Lampions (which require 160 DEX, but could have a max clean attack of 68wa, with 7 slots remaining, and max 103wa).

Why?
- not all gear can be scrolled with LUK, such as helmets / face accessory / eye accessory (unless you chaos a Ludi-PQ glasses)/ pants (unless you scroll perfect +10x30% LUK overalls), and to optimize STATS from scrolled gear, scrolling a high DEX helm/face accessory/eye accessory/pants, you can push your total DEX up to equip a higher level claw

- with the best end-game DEX gear, you can have 30-40 DEX base, and gain 24 more weapon attack from wearing a max attack Lampion (103-79), only to sacrifice 5-15 more DEX onto base AP. That's considering you have the extreme OP outlier DEX-gear though. Even if you need to sacrifice 10 more base DEX for 10 more weapon attack gain, it is still worth it.
- realistically speaking, you can have 25 base DEX and wear a +7 Dragon sleve (90wa) or +7 Speargrave (92wa). That itself keeps you DEX-less but with 11-13wa above a perfect NRC.
- averagely speaking, even if you have mid-tier DEX gear, and add about 5-15 more DEX (into 30-40 base dex), you sacrifice only 10more DEX for 11-13wa, and 10wa for 10 DEX (ie. 10 LUK gain from saving 10 DEX) should be opted any day.


LOW LEVEL STRATEGY
Since NRC requires 0 DEX, at a lower level you can optimize your damage by going pure LUK, and self-scrolling some cheap LUK gears like bathrobes, earrings, and getting a cheap maple claw/kandayo/NRC, but all the while saving mesos for a good mid-tier DEX gear.

This is to allow yourself to play your assassin with some damage while preparing yourself for low-DEX transition as you level up above 90 into 4th job. Buy gears like 10-12 DEX earrings, 14-18 DEX pants, 6-8 DEX face accessory and scroll a 30+ DEX helmet, and then slowly make your way up by improving those DEX gears. Eye accessory is more expensive, but if you can afford a 7+DEX, that could hold you till you're end-game.

Sweaty Tip:
As a night lord at level 200 with MapleWarrior20, 1 weapon attack averages to about 6 LUK.
If going DEX-less equates to saving an equal amount of base LUK (excluding MapleWarrior calculations), compare sacrificing 10 DEX for 10wa.
That's estimating a sacrifice of 10 DEX for 60 LUK (10 x 6 LUK = 60 LUK).

 

how does one get this "cheap maple claw..." you spoke of? I am new and have been told they dont drop anymore and the people who have them charge like 25m for a maple claw

 

Owl for a cheap scrolled one and try your luck.
I think aiming for a high attack one is definitely gonna be expensive (like Skanda)