The bigger problem I had with clipless was not falling but getting my foot clipped in. Many times I had to keep tap dancing on my pedal to get it to clip. Eventually, when I stopped looking at my foot and simply let it clip in naturally, it worked; but it took some time and frustration. I also didn't notice much improvement using clipless over toe straps. What about using an open cage kind of toe clip first? It will make a big difference over a simple platform and get you acclimated to having your foot feel attached to the pedal without any learning curve. Very inexpensive and easy to attach. Won't have the same effect as clipless but probably a good transition from platform with no attachment at all.