There should be an option to order the checklist inside tasks, otherwise they get ordered as you input each checklist item.
Suggested by: Pedro Soares
Just an idea, if you want to know an opinion of what would be intuitive. If someone tries to do something and can't, my guess is that the first way they tried it is most intuitive to them. I tried dragging and dropping them and ended up checking and selecting instead.
I stumbled across this looking for how to re-order the items, and I am a bit disappointed that I now I have to delete all my checklist items, since I copied and pasted them in reverse order thinking I could fix it later.