Which weapon enchantment..

[Kazumetsa Raijin]

Is there any weapon enchantment I could use that could cripple my foe? Like something that applies shaken, drop in AC, crushes his movement, etc.

[Imbicatus]

Cruel, Ominous, and anchoring seem to so what you want, but none of them are really any good. The best method would be to have a spell storing weapon that has a good spell for that stored.

[Kazumetsa Raijin]

Hmm, Spell Storing. Interesting... can that store any spell I wish?

[Imbicatus]

Any spell of third level or under. The only problem is once you use it, you have to recast the spell into the weapon. This really only makes it worthwhile if you can cast spells yourself, or if you can convince the party spellcasters to top off your weapon.

[Tormad]

If you are looking for a way to apply some battle field control, have you looked at the feat Dazing Assault?

Its a feat, but you take a -5 to hit but then every attack you connect with has a change of dazing the opponent. I know you were looking for a weapon enchant and this is a bab +11.

Hope this helps.