Is it the vibratos? Is it the consistent note hitting in which defines a good singer? To most producers I know, those are just the basic that all singers should have. It’s like asking whether a pro gamer can perform the most basics of mechanics in the game. Of course we’re talking about real singers, not just a person who does it for fun.
The thing about a good singer always boils down to one thing, which is being able to express a song perfectly according to the backing track, or a lyric. It is by far the most difficult thing to do compared to the technicalities. A person who is able to pull high level singing techniques wouldn’t compare to someone who has mediocre techniques but have high emotional connections to a song being sung.
There are a ton of really great singers throughout the century, these people express the song perfectly on their tracks, and provide high level techniques of singing. These include but are not limited to: Michael Jackson, Kendrick Lamar, Christina Aguilera, Chester Bennington and much more. To all my fellow friends that want to pursue singing as a carreer, focus on the emotion!