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Firstly, the term "crop sensor" is a misnomer, and I only use it in the above title to explain the misunderstanding and promotional agenda.
The implication is that 35mm is the holy grail of digital formats to which we all must aspire, and smaller formats are mere crops of the "real deal".
APS-C and 4/3 or no more crops of 35mm than 35mm is a crop of medium format. Each is its own format. Yes we can compare the relative strengths and weaknesses, but bigger isn't necessarily better; just different.