A very useful tool would be a command that allows you to select a line segment and quickly switch this to:
tangent arc
smooth arc
arc
straight
The reason why is for design and takeoffs. Sometimes you may want to blow in a bulk of the lines and then go back and modify individual sections to better fit criteria.
I like the Quick Line macro for this reason, default is straight segment but if you hold down CTRL it will create a tangent arc segment instead.
I would love if there were additional modifier key combinations added to further augment the behavior - e.g. maybe holding Alt would force ignore elevation when snapping or CTRL-Shift could draw smooth curves. Maybe pressing āPā while the tool is active could toggle line definition by Point ID and āOā could toggle station/offset mode. āDā could jump to deflection mode, etc.