Wow- how aggravating, could this be a design restriction in the air filter box (too little air flow?).
I found with some older echo leaf blowers the air box was noise muffled but I got some improvements in throttle response by adding a few small air holes in the filter cover, and retuning the carb. Maybe there is a different carb that can be adapted, but owners should not have to go thru that.
It does sound like something basically wrong with the carb selection or something in the fuel supply system.