Good, better, best. It comes down to definitions and criteria. It also includes personal experience, style and preference. Unless we can agree on how we measure and determine excellence, we cannot agree on the evaluation.
Someone may say that John Doe is the best quarterback because he has the most completed passes per game. Someone else could say John Smith is the best because he has the highest percentage of completed passes per game. Different measurements. Doe throws an average of 100 passes per game and completes 50 of them. His percentage is 50%. Smith throws only 20 passes per game, but he completes 18 of them, for a 90% success rate. Then you have Joe Jones, who has only a 40% completion rate, but it is because the receivers suck, and they miss or drop passes that a competent player would catch. Or what about Peter Peterson who has an average completion rate but also can scramble for running yardage, and is known for his brilliant play calls? And we haven't talked about those fans who like Gordon Gorgeous for his strikingly good looks in the underwear commercials he stars in, or Tim Tango for having appeared on Dancing with the Stars. You get the picture.
Adam currently has an incredibly high awareness level for a pop singer, and an amazingly high approval level, thanks to recent gigs. I am not interested in what some stranger half a world away with no known musical or vocal training has to say about how he compares to Freddie. I have my own ears. My own eyes. My own training. My own experience. I trust ME more than I trust some anonymous internet poster.
I do believe that one possible reason for the criticism we occasionally read is because Adam is so damned good. There hasn't been a singer who has appeared with Queen who could match Freddie for range. Adam's range, at least live, surpasses Freddie's recorded live performances. Adam's voice also sounds like he has more power; something Freddie was known for.
People who have formal voice training and a classical music background can give you plenty of criteria for what makes a "great" singer, and Adam, having so much classical training and singing experience, demonstrates those criteria to a greater degree than Freddie. That's just a fact. However, if a listener does not agree with those criteria for excellence, then Freddie may be the "better" singer. Apples and Oranges.
Then you have the fact that Adam has the theatrical background and stage presence that few pop/rock singers have. Freddie has pretty much cornered the market on that for many years, and Adam is perhaps the first to demonstrate that theatricality, humor and campness like Freddie did. He is not imitating Freddie. He is being himself. But, he is a compelling front man.
Everyone's perception of beauty and sex appeal may be slightly different, but to many, Adam is better looking, more classically beautiful than Freddie. Adam certainly oozes sensuality and sexual power on stage.
Finally, Brian and Roger love Adam. They praise him in every interview. They attribute his talent and personality for the reason they are on tour again. They say their current performances are equal to, if not better than their performances in years past. To some Freddie fans, that sounds a lot like disloyalty or disrespect for Freddie.
I get it that some folks are going to see Adam as a threat to Freddie's legacy. That doesn't mean I agree with their assessment. I also get it that some folks like voices with different techniques, ranges and styles from Adam. And with different stage personas. And different fashion sense. S'okay. There are plenty of artists around for everyone to find a favorite. I think Adam has and will have enough fans to make records, appearances and sing concerts for years to come. That's where my focus is.