I like the "develop" something first and "enhance" it later approach. To me, the horse stance training belong to the "enhancement". I prefer the following MA development order.
1. development - through partner training,
2. test - through sparring/wrestling,
3. polish - through solo drills.
4. enhance - through weight/equipment and static standing.
What's more important, the "fighting experience development" or the "foundation development"? Of course both are important. But there are some "time" issue here. You can still "enhance" your horse stance when you are 60 years old. But you can't enhance your sparring in your old age. So when you are still young, you should spend most of your training time to develop your "fighting skill". You can always enhance your foundation for the rest of your life.
IMO, it's better to drill your "hip throw - dynamic horse stance" 10,000 times than to stand in your "static horse stance" for 6 months. You will get the same result for your "static horse stance" training, but you will get much more.