Yes you can, but you're in the wrong mindset for a thief. Thieves aren't built to kill, they are built to steal AND get away. You'll never want to be caught standing around with a freshly stolen item in your pack since you can't perform any other skills for 10 seconds right after a successful theft.
Wrestling works for a thief because of the empty hands requirement and the fact that wrestling skill counts as a combat skill and so your DCI comes into play. Without a combat skill your going to have 0 defense even if your suit says 45 DCI. Wrestling stun/disarm also plays into the "get away" mentality, it's not going to kill a seasoned target.
Consider getting rid of ninitsu too, seriously. You can lower hiding and stealth to 80 each and never fail in medable armor but if you want ninjitsu for DS you not only need 120 ninjitsu but you need 100 hiding and probably 120 stealth for decent damage. It's a lot of points!
Check it out....
120 stealing
120 wrestling
100 magery
100 Snooping
100 Detect
100 Tracking
100 lockpicking
80 hiding
80 stealth
-------------------
900 total (180 over cap)
That template has it all, lockpicking for dungeon chests or exodus detecting/opening chests, snooping for players, tracking and detect to find hidden players in fel, magery for full utility(heals, cures, summons, marking, teleport etc)... it has everything. It's 180 over cap, is that super expensive or even possible? Yup, the cost will be in the 120 power scrolls for stealing and wrestling, the rest is cheap...
100 pts from jewels(30 stealth, 30 mage, 20 wrestle, 20 stealing)
30 pts from Burgler's Bandana (10 snooping, 10 stealing, 10 stealth)
10 pts in stealth from +10 robe
40 pts from shadow dancer leggings (20 stealth, 20 stealing)
Training is easy too, you just buy 10 stealth and the other 70 comes from items and done. 70 magery, 70 stealing... same thing. It's not hard to build since you don't have to actually get to 100 on the expensive skills. The suit: 70's resist, 100% lrc, 45 lmc, 45 DCI etc... not hard to do with a legendary or all player made. The end result is a thief that can do anything/everything but his fighting is designed to give him time to escape, not to kill. Works in pvp and pvm, stun, cast invis and walk away. You don't get animal form but you can't use skills/specials in animal form anyway. Have a macro rdy to cast invis if hiding fails(it rarely will unless a monster is too close), mount up and run.
The synergy between thief and wrestling, and the 3 items mentioned above, give you an exceptional thief BUT... you have to get out of the kill mentality for a thief, you don't care about killing, just getting away.
P.S. you can remove something like snooping if you won't be stealing from players and add something like resisting spells if you spend time in doom and are constantly getting cursed. Or you can add eval instead and equip a spellbook with +10 magery to get a summoned demon to beat up some monsters for you if you need that. It all depends on your playstyle.
I can't help you if you are wanting a DS thief for PvP, I'd preper using a toon built for pvp to do that. As a thief you have too many pts tied up in non-pvp skills to compete vs skilled players.