I also don't think she sounded that bad... But then my train of thought changes its course and I find myself thinking that any semi-decent karaoke singer would be able to sing just as well, and I simply get crestfallen I mean, it's Mariah Carey we're talking about, she is synonymous with vocal excellence! Now she relies on pre-recorded vocals way to much. If it was Britney or whatever, that would be understandable - she pretty much has no singing reputation to uphold, and that's why her concerts are (I imagine) mostly focused on dancing and visual spectacles. Mariah's thing has always been something different. I don't expect that at that age and after all this touring and promoting year after year (plus nodules) she should always be at the top of her game, but like I said, it's just a depressing thought to entertain that some intermediately skilled randos in a bar could outsing her now, judging from what we've seen recently. Sure, she's also behind all her songs when it comes to melodies, lyrics and even production, but as far as actual live delivery is concerned, you know, she's kind of sub-par at the moment. Adapting her songs, even if it means changing them dramatically, has really become a necessity, which is not a bad thing, because her repeirtoire has always been the singing Mount Everest. But her struggling to sing, and being picked on for it, truly does no good to anyone.
I definitely don't think she should retire, wtf, (unless, of course, that's what she wants). MIAM is a great album, and she's had great performances in the past years, but 2017 so far is looking kind of bleak. Hopefully she fulfils everyone's expectations with the forthcoming tour and concerts; she doesn't have to be stellar, but good enough to at least not get articles written about her poor voice or whatever.
At the end of the day, as a recent fan I've still got a lot to explore and marvel at, becuase she's definitely proven herself the best voice of pop music.