As a "seasoned theatergoer" of numerous decades myself, I would never presume to speak for that or any other group, as we are all individuals with varying viewpoints. Everyone is entitled to his/her/their own opinion. I do find it odd, though, and contrary to fact that some people find no character arc in Harold Hill in the current revival. Perhaps they are not paying close enough attention? More examples abound, but these stand out: Early in the show, as Harold distracts the town council members and sneaks away into the wings, he's gleeful about his manipulation. Later, as he indulges in the same subterfuge, his mien changes as he temporarily halts his getaway, looks at the people he is deceiving and walks slowly away, clearly re-evaluating his actions. It's very clear on his face that he's undergoing a change of thought. And finally toward the end, the look in his eyes and his surprise-filled gasp "oh!" as he reads the page Marian tore from the Indiana Journal and gave to him says a lot about his realization and final character morph even in that single utterance.
I've seen the show more than once and never heard a slip of accent or faulty enunciation.
I cannot comment on Max Clayton's Harold Hill, as I did not see the show with him in that role. I appreciate that many of his fans applauded his portrayal. However, I did see him twice cover for Remy Auberjonois in the Charlie Cowell role. I much preferred Remy. Mr. Clayton raced through his lines and did not convey anywhere near the apoplectic anger and malice conjured so deliciously by Remy. Whether those were Mr. Clayton's choices or the director's I do not know.
I hope for and am very much looking forward to this revival cast recording with the original principals.