Daemon Prince has the Doomstone, Mossy.
However, I don't think the Doomstone works best there, unless you face opponents with a lot of characters in a single unit. The Prince should handle most single character units on it's own. If you aren't looking for a list like Mossy linked, the removal of the Doomstone should probably lead to the removal of the chariots as well.
Possible changes might include another Horror or Bloodletter squad, or another heavy hitter, like a Soulgrinder who would bring long range shooting power. Typically, you should have a couple more troop choices at 1500. This list doesn't have an abundance of wide spread killing power in my mind, and would benefit from more objective grabbing troops as I see the potential for drawn out combats.
My likes and preferences, as well as what works in my local, won't adequately represent what you experience. If you like the initial list and think it will be fun, give it a spin. If you're looking for something more competitive, I probably wouldn't go Tzeentch, they were big last codex and saw a big reduction this go around.