Kelly,
I just had a SA with a 59 in my shop today (which is interesting cause I thought John favored the 56 blowers), I don't disagree with what you are saying, but I will say your math is a bit off, 4 two inch hoses do not equal a 4" port, let alone bigger. And when you couple those 2" hoses to a plastic barbed connector, it's less than 2", so you aren't even getting a full 2" diameter.
Fortunately I know you are a better mechanic than a math teacher.
The unit I saw today, was very well built, very simple, very solid, just had some choked down intake plumbing, this fellow is gonna trip when he converts the machine to 2.5".
I've had several ask for 3" and 4" manifolds for the blower with multiple 2.5" ports coming off(what I call the octopus), but I told them they would also have to change out the tank fittings....too much work, so we just work with the wand side of the tank for now.
Those in-tank blower filters are silly, do they really use the tiny filters on all the machines? Seriously, I'd just take em off, the tank has a 2ft. lint bag.