Ok, let's run some numbers on elusive target! YAY! numbers!
First some #defines
Dodge 44 = 0.56 chance of being hit
Dodge 48 = 0.52 chance of being hit
Dodge 58 = 0.42 chance of being hit
AC < 200 = 0.95 chance of being hit (It seems to me that in LE 200 AC is the starting point of useful)
Elusive target = 0.95 chance of being hit
Ninja Spy Incorp = 0.75 chance of being hit
Displacement = 0.5 chance of being hit
Total chance of being hit is equal to the product of all the hit chances of the parts that make up the defensive miss chance.
Thus dodge 44, elusive target, ninja spy incorp, AC < 200, and displacement would be
0.56*0.95*0.75*0.95*0.5 = 0.1895
so you get hit 18.95% of the time;
Dodge 44, ninja spy incorp, AC <200, and displacement = 19.95%
Thus at 44 dodge, with ninja spy incorp, non-significant AC, and displacement, elusive target makes a 1% difference(rounded to 1/100th of a percent).
How much does adding 4 dodge change this?
Dodge 48, elusive target, ninja spy incorp, AC < 200, displacment = 17.60%
Dodge 48, ninja spy incorp, AC <200, displacement = 18.53%
Thus elusive target is worth about 0.87% evasiveness for WAI evasion types at 48 dodge. Why, yes, that is over twice the amount that you claimed it is worth! Is someone relying on bugged stacking of particular abilities in calculating their miss chance?
And 4 dodge vs elusive target is worth about 0.43%, a trivial difference according to some. Yes, I would trade elusive target for 20 PRR and take the 4% dodge at 30 if they let me.
Removing displacement(eg vs TS mobs) results in the effective differences being doubled.
How much HP is this worth? well, that depends on how much the mobs are hitting you for. If you get hit for around 1000 points of damage(not unreasonable with around 150prr in LE shroud), elusive target is worth about 9 hp per attack - so you get the same value of toughness every 4th attack, which also happens to be the tipping point for when you are more likely to have been hit than missed ( [1-.176]**3 = 0.56; [1-.176]**4 = 0.46).
Thus, in terms of staying alive elusive target remains best-in-slot for builds like this (unless you position poorly, have bad saves, don't invest in making an SR belt and get CC'd a lot, in which case you want to pick up forced escape)
Obviously there are better choices to improve damage, but hey, I didn't say best in slot overall, just best in slot for the not-dying staying alive options.
Of interest:
Dodge 58(max stable w/ ninja spy incorp), elusive target, ninja spy incorp, displacemnt, AC < 200:
14.21% chance of being hit. Tipping point of getting hit is every 5th attack. (about 54% chance of being hit by the 5th attack)