I think adding a feature where the user can test out their base layout by a raid on your own base. It wouldn't change much because it doesn't change gameplay or other users experiences when in use or after. The point of this would be to test your bases practicality and efficiency, eg: "can my base sustain a raid consisting of hog riders and minions with 2 rage spells and a healing spell?" To make it fair the user should only be able to use the troops in their camps. This would be to prevent players without dark elixir from being able to test out the new lava hound. (They should have to play long enough to earn it.) lastly I don't think that you should have to "use up your troops" on this feature (personally I think they should be simulations and kept alive for real battle because you don't gain any trophies or resources), but if this would be too much of an advantage in your eyes (I'm assuming you are authorized to make changes), you could have the player spend elixir or even a small amount of gems for the use of this feature.
Thank you for reading this sincerely ~wildrino [chases top three]