The feat, as written, would not let you change the weapon type for enchantment purposes.
Also, I might make it part of a two feat chain with a bit less power in the feat.
First would be Improved Subdual where you get to strike for subdual damage with any weapon at no penalty.
Second is the feat under discussion. It is quite powerful because it might allow a weapon to damage something it otherwise could not. It still would not change the weapons base type for enchantment purposes.
I would allow it to change the weapon type, I think under the following circumstances:
1. Both feats I set out above are required, but the second feat simply allows you to strike with the weapon in an unusual manner at a-4 penalty (non-proficiency)
2. You need to take the Exotic Weapon Proficiency feat to wield a weapon properly in this unusual way - and, at that point, you may enchant it in this mode as well, but such enchantments are ONLY effective if one has all the feats needed to use it properly.
To make it clearer; your Spiked Chain could have the Disruption property, but it would ONLY work if you have the Exotic Weapon Proficient: "Use Spiked Chain as Bludgeoning,” which requires the two other feats first. Anyone else using your Spiked Chain would find the Disruption enchantment simply did not work.
I'd do it this way to allow you to have the choices you want, but they would be very expensive for the character.