I'd only consider wireheading equivalent to death from an outsider's perspective. It's interesting that you'd treat converting a suicidal person into someone modded to happiness worse than a suicidal person ceasing to exist; I can think of a few possible reasons for that, but the only one that appeals to me personally is that a wireheaded person would be a resource drain. (The others strike me as avoidable given a sufficiently patient wireheader overlord, rather than the "just pump them full of orgasmium" overlord).