I'm no coder, but I can see multiple major issues here.
First, current setup is very, very simple. There's smoke and fire, fire makes smoke. So the only element combos are air, fire, and smoking fire.
Other things would provide many problems. Ie, what happens if rolling smoke hits rolling radiation? Does one overright the other? Do both exist simoltaniously? Does a mix interact differently? How is this expressed in the ui?
Proliferation is the real issue. Smoke and fire are incredibly easy, because its 2 total elements that work together. Throw fire in smoke, fire smoke, throw smoke on fire, fire smoke. Adding in only 3 extra elements, on a ui level alone, would be a problem. How would you clearly display 5 elements in 1 tile?
Beyond ui, proliferation of such things. Tracking life span of smoke radiation, poison gas, ect, as they bump into, or possibly mix with each other.
I wouldn't call it impossible outright, since, at least the ui could be changed by flashing through multiple ui elements, but proliferation and tracking all the data might be an issue. Its also a cool idea, but more difficult than you might think.