Maybe half lap the X sections or use a standard mortice and tenon. The same with the stretcher.
With the domino I was able to set out the tenons (2 on each joint) so that the stretcher tenons didn't come in the same place, therefore creating a weaker joint. So possibly the best alternative would be a half lap joint on the X section then a standard tenon on the stretcher. (Hope that all makes sense!)
That looks a lovely table and from your picture seems to compliment the décor very nicely. Just out of interest how would you rate the strength provided by dominos in this sort of application vs more trad joinery?