My opinion is the same as I had when I was creating races for WCS mod: I don't see reason to create something which is already exist.
However, if making trainer of your own makes you happy, then that's okay. But you must be motivated to reach your goal, because I...welp, at least I don't have that motivation you seem to have. But also, I don't really play DF anymore so that's why I am not bothered of thinking trainer creating. I just stay with swf stuff as long as I can...and want.
What ever you are trying to reach, good luck with it :3