Yeah, so this wasn't entirely unexpected. Like with Kurt Cobain, her death was paradoxically logical and unnecessary -- logical because we've all seen this movie before, and uneccessary needs no explanation. They slowly went about ruining their lives, died, and we all watched.
I actually had some hope for Winehouse after seeing the now even more infamous "performance" from Belgrade. She looked healthy, not emaciated like in years past. She was out of it, but she'd looked much worse on stage before. Instead of being half asleep and mumbling along in a drug-induced stupor, she seemed confused, maybe even a little bit scared, like she had no idea how she ended up on stage. She looked less like a drug addict than an amnesia patient. I felt a little bit sorry for her, which wasn't the case for past performances when she was even more obviously wasted.
Many people said that Winehouse had an extraordinary talent, but I never heard it. She was talented, yes, she had a great voice, definitely, but she wasn't a singularly great, arresting, stop dead in your tracks sort of talent. To compare her to someone whose name will be coming up a lot in the next few days, she didn't have Janis Joplin's voice. Joplin's voice still sounds blindingly powerful and unique even forty years later. However, while she might have been a success during her life, Joplin only became a phenomenon after her death. Amy Winehouse was a much bigger star than Janis Joplin, and she had a far greater influence on the music industry. Plenty of bands were peddling blues-y pysch in late 60's San Francisco. Winehouse carved out an entirely new niche for herself in the pop landscape, practically created and championed a new genre of music to an unsuspecting public, and sold millions of records via the twin threat of her talent mixed with her ubiquitous personality cult. She cleaned up at the Grammys like few female artists ever had, and "Back to Black" was the third biggest selling album in the UK in the 2000's. Before Winehouse, the music landscape was filled with far too many cookie cutter R&B divas with nary a distinctive voice or sense of fashion to be found (of course there are some exceptions, e.g. Pink). Without Winehouse, mega-hits like Beyonce's "Single Ladies" wouldn't have existed, and Adele would have had an immeasurably larger barrier to superstardom.