Masters of the Sword: A Warblade's Handbook [Under Construction]

[Essence_of_War]

It is actually very much like Monkey Grip in that it gives you a miniscule damage return for the feat investment. If you 100% have to make a chaotic good dark elf ranger who wields two scimitars...sure, take the feat. If you're trying to do any sort of practical optimization, it probably isn't worth your time/feat investment etc unless you find a way to get it for free.

For a warblade, the difference amounts to:

"Do I spend a feat on Exotic Weapon Prof. and wield two kukris, or do I take Oversize 2xWpn and wield two scimitars"

The latter is a terrible choice because:
1) Weapon Aptitude means the Warblade can use any weapon ever made with the exotic weapon prof. feat, oversized gives him nothing.
2) The damage increase from Oversized is trivial even compared with weapon specialization.
3) It robs the warblade of his ability to use the kukris in a grapple (if it comes to that, the scimitars are strictly worse)

Evidently Kukri's are still martial weapons

This actually makes the comparison worse, it isn't a choice between mandatory feats, it is just "do we choose a feat that can optimisitcally give you +6 extra damage on a full attack". Elfin is right, I don't think that it is worth a feat slot.