Cakewalk already remembers per-track information about recently used VST parameters (to show a shortened list of parameters in the automation sub-submenu for plugins), and this could probably be re-used for the following:
instead of just pressing the automation "+" button, the user would be able to hold it (similar to how picking a Snap note works), which displays a dropdown menu with 5-10 most recently used plugin parameters for this track
releasing the mouse click above a parameter would add it as an automation lane
(optional) right-clicking the "+" button would display a dropdown menu with the same 5-10 most recently used parameters, but each one would be selectable (e.g. checkbox), and at the bottom you can click "Add Selected" to add all of them at once as automation lanes
(optional) user can select in 'Editing' settings how many "most recently used" automation parameters to show in the dropdown menu
As an alternative, it would also be great if there was a new button in the VST host window (next to the trio of 'S', 'R', 'W') called e.g. "A+", which adds the last touched parameter to the automation lanes of the track the plugin is in, and hovering over the A+ button would show which parameter would be added if it was pressed right now (in case the plugin doesn't clearly show which knob/fader was touched last).
Maybe this is a smaller issue for people using automation Write and automating using Midi controllers, but I think for those mostly using a mouse and drawing automations in, the workflow of adding a VST parameter as automation could be made much more "frictionless" by adding these functions into Cakewalk.