It would damage irrigation canals and water supply around Yuma and Mexicali and the constant refilling would diminish water around those areas. The lake itself would cover valuable farmland. Additionally, it would need drainage channels to remove the salt that naturally builds up in the lake. The climate benefits the lake produces are marginal--most precipitation will fall on the nearby mountains anyway.
It's more beneficial IMO to leave the Salton Sea healthy and unpolluted with saltwater fishing and tourism. Lake Cahuilla is ephemeral, especially as a freshwater lake, and it seems too difficult to try and force nature into accepting a compromise without serious engineering (i.e. bringing in water from icebergs or maybe even going to space and importing it from comets).
Now the desalination plants are 100% viable as Saudi Arabia and even the very overbudget plant in Carlsbad has proved. Also keep in mind that a hypothetical state of northern California would be entitled to 0% of the Colorado's flow, although California itself might be allotted less water meaning the other states would get more (Mexico probably won't).
But Freud’s theories were already the dominant approach in counseling, in explaining human behavior, etc.