I don`t think Barcelona is "rock meets opera" per se. I don`t see the "rock" part. It`s not an album you can label anyway.
IMO frontmen as great as Fred, there are several. Robert Plant for example. Some might prefer one or the other, but imo they`re at the same level. Queen influenced many bands but it wasn`t the only influence of any of them. GnR without Queen influences would lose only a slight part of their background. Even Axl - who is perhaps the biggest admirer of the band between them - wouldn`t lose a very big part of his inspiration. First, even if he liked Queen a lot, he liked many more, so it`s the brick in the wall point. Second, he`d never know about Freddie or Queen because they wouldn`t exist. Therefore they wouldn`t have been missed.
Hotel California is fairly basic for being such a big anomaly as Bo Rhap. They`re equally great and lovable, but the "novelty" of Bo Rhap, besides being the (not really) first video, was the fact that it apparently broke all rules. Hotel California, on the other hand, even being long, didn`t break any: Two contrasting sections (verse, which lasts sixteen measures, and middle-eight, which lasts... eight measures, duh), a crescendo intro (adding instruments bit by bit), diatonic driven harmony with ocassional parallels included (F# in the key of Bm), middle-eight beginning in one of the neighbour tones (G in this case), AA` phrasing in that section, etc.
Which would be studied as the ultimate clever meets catchy masterpiece? Perhaps Stairway, or Las Ketchup Song. Not to forget Mambo Number Five.
John hated Hot Space. Fred's favourite singer was not Paul Rodgers. Roger didn't compose 'Innuendo.' Witness testimonies are often inaccurate. Wales is not in England. 'Bo Rhap' hasn't got 180 voices.