I design HVAC for residential single-family and some multi-family homes. We run flex ducts from a plenum and use wyes randomly along the duct run.
What I'd like to see is:
1.) The ability to insert a duct fitting (wye) into a flex duct run the way we can with rigid duct.
2.) The ability to edit flex duct with grips as if it were an array line. This way, I can run flex ducts and then stretch out the flex ducts in the x, y, and z axis to prevent interference. As MEP 2010 sits now, I have to anticipate these interferences in before hand or else start the duct run over.
3.) The ability to use "Duct Length" with flex ducts the way we can with rigid duct. Our flex duct comes in 25 ft. lengths which any single duct run longer than that requires a "splice collar".