I'm not sure that snakes would make good habitat animals. Many species are sedentary and do not move a great deal. It would be extremely difficult to provide the heat and humidity requirements for a large snake in an outdoors enclosure, as mentioned above. They are superb escape artists and will get over most walls, fences and barriers with ease. Finally, there's food. Will Frontier want to animate snakes engulfing other animals whole?
I guess all of the above could be overcome by effectively sacrificing some realism and ignoring them, but I just think snakes work better as exhibit animals. Granted, I'd want to see bigger exhibits if we were getting giants like the green anaconda and reticulated python.