The functionality of the MEP modeler is incredibly lacking in customizaibility of the selected object in the Info box in comparison to basically any other Archicad object. In MEP coordination workflows, the most commonly changed parameter of the systems (especially HVAC) is connection dimeisions. The next most accessed parameters that can't be changed without opening the tool settings dialog box are: diameters (for elbows especially), and MEP systems. All of these are simple text parameters that could be typed in without opening anything.
And to top it up, the MEP systems don't change the most important parameter of the objects (especially straight segments of pipes and HVAC tubes), which is the connection symbol pen 1 in all settings. In coordination of all the MEP systems it is critical to have the ability to quickly discern between the systems used in the project (I'm talking about the vertically rising pipes and so). Being unable to set the 2D reprezentation in severely damages the ability to create documentation quickly and adjust systems without having to go through half of the available options just to adjust those most commonly needed.
The last thing that is missing in the info box is the ability to change radius of elbows and connection length/angle on tees and other similar object types.