I tend to doubt that implants would do much good for an adult who was born deaf. The human brain is an adaptive organ that actually changes its structure somewhat depending on stimuli over time. For example, brain studies have shown that a certain structure in the brain is different for children who've studied music at an early age as compared to those who don't. Simply wiring an implant to an adult who was born deaf could well result in a situation where the signals get to the brain but it has no way to process them. I suspect it'd be different for a younger child or for someone who lost his hearing as an adult.

From what I've read, some in the deaf community are hostile towards implants because they don't see deafness as something that needs to be cured. Just as someone who was born blind would have a hard time understanding color, those who've never heard might well have little idea what they're missing.

I see implants as a matter of personal choice. One of my brothers-in-law has a deaf grandson. Despite early detection and all of the best training, he lags behind other children his age. He might well have benefitted from implants had they been available 16 years ago. If I were to lose my hearing, I'd probably go for an implant.