An obvious one is whether or not it is likely to be used more widely in the future of medicine. Here you could discuss the different vectors for gene therapy (viral, non-living, etc.), the safety of each one, the efficacy of each one then conclude about the likelihood of its use in the healthcare system. This allows for debate easily as you could say "they are safe because blah blah" "however blah blah suggests its not" and has a big scope of research (I did a little bit about viral gene therapy in mine and there seemed to be quite a bit there).
Hope I've helped!