You are correct, the small screen would make typing impossible with almost any keyboard because the key selection would have to be so precise, but with flicktype only the pattern of the key location is needed for the keyboard to recognize the word. So only FlickType will work on the watch.

I tried an early experimental version of the FlickType keyboard for the apple watch, and I was amazed how well I could type with it! Of courts, there is nothing that I could use the text for, the watch does not support text input, but there is Potential for a container type app that could export text.😎

Keep your fingers crossed.