Indeed, you are correct! It seems that TCM has, in making changes at their Website, they eliminated the "request" section. However, I have found a "back door" in the form of a TCM "Help Center" option where I believe that we can still express, among other things, a film or films we would like to see! here is the address (and I have changed our TCM link accordingly!):
I just used this link myself, and, indeed, this is the correct means to make a film request. After making your request and filling in the other required information, use their droop-down and click on "Film Request." You can even include an attachment!
Take care, and thank you for alerting me about this!