Here's just one: Even talking about posthuman psychological superhealth is morally frivolous. Another? Promoting superhappiness may lead to what one may call, informally, "inappropriate" behavioural responses.
N. Forgo, M. Goralczyk, und S. Hanold. Engineering in Medicine and Biology Society (EMBC), 2013 35th Annual International Conference of the IEEE, Seite 4187-4190. (2013)