Monk//CW Samurai strikes me as the worst possible combination.
The classes simply ruin each other. For instance
The Pros:
-Max BAB and Saves. This is pretty good, but nothing Fighter/Monk or Barbarian/Wizard or Paladin/Rogue couldn't have.
The Cons:
-Swords vs. Flurry. They cannot both use their Swords and use Flurry of blows at the same time, they must choose between one or the other essentially losing all combat benefits of the other class.
-Armor vs Nekkid. Samurai can wear heavy armor, it is the source of his AC. Monk cannot use any of his abilities while armored, ruining an important defensive option from the samurai.
-5 Ability Dependant. To make use of all the class features you need high Strength, Constitution, Wisdom, Charisma, and (assuming you aren't using armor) Dexterity.
-Poor As Dirt. To support this dependency this character would have to spend nearly all their money on stat boosting items just to survive. Skimping on Strength reduces damage, skimping on dexterity reduces AC and Initiative, skimping on Constitution reduces his hp, Wisdom would leave him with crap DCs, Charisma would ruin his intimidation tricks. To get +6 to all 5 would cost 180,000gp. A huge investment.
-Dumber Than Dirt. Races or flaws could be taken to mitigate this problem, but since he needs 5 of the six primary stats the only one left to dump is int. Assuming he starts with low int, then takes a penalty to it (half-orc maybe?). He is probably only getting 2 - 3 skill points per level. That is barely, BARELY enough to support his 3 key skills (Intimidate, Tumble, Iajutsu Focus). This means he cannot climb, or swim, or hide, or bluff. None of that.
-No Magic For You. UMD is right out, even attempting to buy it CC is out since he has no skill points to spend. He little to no wealth to spend on items for body slots and his sluggish damage and unimpressive hp and feat selection set him far from first pick on the party buff wagon.
So basically the two worst base classes in DnD are both eastern themed. But when you put them together they get alone like the Korean border patrol (read: poorly). End result is a combo without a single shred of synergy, that goes so far as using class features of one class stops you from using the other class...pretty much completely.