Modern receiver design has to look at all receiver's 'stages' and components to define which will to the limiting stage for 'blocking' or non-linear response to a given maximum receiver input specification. There will always be some limit somewhere in a receiver's design and that is what will establish part (along with it's noise floor spec) the reciever's dynamic range specification, correct? An AGC circuit controling an input attenuator can be useful in some receiver designs to deal with some component limits such as IF filters, detectors, mixer's, etc.