A physical / pierce dual wield blademaster can do better than fine through normal, and probably beyond.
Grimcalc (1 possible build, through to about end of normal):
http://grimcalc.com/build/1008-n3fv9B
The secret Blood Grove vendor sells good dual wield swords for normal, with +2 to shadow strike as a standard mod. A pair of those with Attack Damage Converted to Health on even 1 of them and you’ll have good damage and decent sustain. You’ll still need to back off from time to time, while heal potions come off cooldown, so you can’t ignore the gyrations of your blademaster’s life orb. Ground effects can be quite dangerous, in my experience, so you want to try to avoid standing in pools of dangerous stuff when you can.
Key skills:
The build relies on strong defense, good crowd control, a heal when needed, Healing Rain from Tree of Life (later on), and attack damage converted to health. Field command helps for getting crits, while Fighting Spirit kicks up your OA and damage even higher, further upping the damage for the assassin’s blade and (later) assassin celestial skills.
Get a scaled hide component on an armor piece to complement scars of battle. You’ll be sitting at 99%-ish absorption for armor, at that point, so then focus on getting your armor score high. Even if you have a random bunch of gear your blademaster will stand up pretty well against most physical damage after that. Also, it’s worth prioritizing getting factions to honored, as that gets you access to ring / amulet and to weapon augments. They make a big difference in patching holes and/or adding to your damage.
I put shadow strike on LMB and blade trap on RMB. I’d often charge in with shadow strike, hit war cry, cast blade trap, cast ring of steel, and then blitz. I rely on default attack and weapon pool skills in between cooldowns for these skills, in most situations.
Make the slaughter relic when you get a chance.
Devotions:
tortoise (5) (turtle shell on field command)
assassin’s blade (5) (assassin’s mark on ring of steel early on)
panther (4)
lizard (3)
sailor’s guide (4)
eel (3)
tree of life (6) (healing rain on Oleron’s rage)
lion (3)
scales of ulcama (6) (tilt the scales on veil of shadow)
minus lion
obelisk of Memnir (3 points only, stop at 150 armor in each slot)
harvestman’s scythe (6)
crossroads primordial (1)
minus eel
assassin (7) (blades of wrath on something with AOE on it, hits lots of mobs)
Hopefully this helps.