Sorry to start a new thread as my first post, but the search turned up nothing on this.
The Hex Blight seems to be a very nice thematic for a wasting curse, the only problem is, when used on a living creature it does not damage their constitution any faster than it heals naturally (one point per day). Adding a factor that arrests natural healing of ability scores (or at least constitution) should aleviate this.
Or even adding more Constitution Damage when you use the hex because it is only 1/day.