What would you call 'poor plumbing'?
I have my pumps half way up the side of the tank and my son has his virtually at the top of his tank. Neither of us have had airlock problems. 'Poor Plumbing' would refer to air leaks on the suction side of the pump from the tank.
Both our tanks outlet sockets were sealed with PTFE tap before the pipe couplings were connected. The reinforced plastic hose was softened with hot water before being squeezed on with 'O' clips. We have Shurflo pumps on our vans and find the filter connected to the pump inlet needs to be carefully tightened up that little bit extra to ensure an airtight seal - its a taper fit.
There is no other way for the pump to draw air into the system.
Spruce