I absolutely love that will be a dummy finally, but I would bring up the following points about the likely cost (at least for a long time after housing release, when they are still rare).

There are 3 types of people that need the dummy:
1) Experienced player who are doing theorycrafting. This group will probably be able to afford a dummy or know someone who has.
2) Console players since they don't have access to addons. Some of this group will have access, some not.
3) Newer players, or players new to DPS. These people are the ones who need it the most, and won't have it.

I think the people who are in most need of a dummy (the poor new player who doesn't realize that they are doing 6k DPS in a dungeon, and that its terrible), will not be able to buy or craft one, and won't be able to improve. There are already a huge number of issues in this game related to the huge jump in difficulty from normal to vet content, if target dummies were easy to acquire it would be a lot easier to suggest to DPS that they require at least say 15k DPS before they start doing vet content.

Summary: Please consider reducing target dummy cost to make it more available to new players.