I've been into Queen since they were on Don Kirshner's Rock Concert and The Midnight Special.
There was a lot of hippie rock out at the time and some glam like Angel, Sweet and others.Queen was definitely a cold slap in the face. Edgey, precise guitar work, soaring, well controlled vocals, operatic, tinged with classical arrangements. All that and with a tight professional stage show.
I think Queen was very influential in bringing classical stylings to what now is metal, as well as making staging and theatrics huge events.
Musically, maybe they could have inserted a different drummer, but they would have lost Roger's extreme high notes. Maybe they could have substituted John Deacon out? Freddie and Brian???? No way. They have a permanent place in my collection.