Currently the network node operators are overwhelmingly supporting 1MByte block limits

Upon what do you base this bald assertion?

Currently any block greater than 1MByte will be rejected as invalid by the vast majority of nodes.

So the fact that, to the average node operator, they have no real alternative -- you are marking that as a solid preference for 1MB blocks?

... there is no way to differentiate between "small legit transactions" and fee-paying spam if they pay the same fee

Can you articulate your definition of 'fee-paying spam'?