I think you might be over valuing attacking even faster. I still think Ranger 18/X is probably better than Paladin 14/Ranger 6.
Even if you allow that the paladin variant would be 10% more DPS, and that really depends on what you are fighting (FE vs. Evil Outsiders) etc....the loss of evasion is huge.
In a lot of cases Evasion > 10% more DPS. Also a lot of the time it really wouldn't be 10% more DPS.
Also, it is possible you will see items with sacred/competence bonus of 5% or something.
The item thing would really diminish the build, if you could get something with a 5% competence bonus to attack speed (seems possible) then you really cut into the power of the build.
Seems kind of risky to me to depend on these two things stacking (and there never being any other way of getting those types of bonus).
Really all they have to do is change items already in the game to competence and you are reduced in power compared to just going more Paladin or Ranger. It is certainly not a bad combo given what we know, but this is one where you are WIDE OPEN to being reduced in power and the changes are not unreasonable or unlikely.
Personally I would go Paladin 18/Monk 2 or Ranger 18/Monk 1/Rogue 1 for a better end game TWF build.
Or if you want something off the wall...
http://forums.ddo.com/showthread.php?t=168761