I think your analysis of the throughput differences between the two strainer is accurate. A bronze hose barb normally reduces the ID of water passage
more than a plastic hose barb so there isn't a lot of difference between 1/2" plastic and 3/4" bronze.
One difference that might be significant is the size of the strainer basket. I don't know how much larger the 3/4" basket is than the 1/2", but the larger basket can contain more sludge and debris before restricting the water
However, since the existing configuration does not appear to be causing any problems I would stay with it.