I want to be able to do this:
1. Set loop, start recording midi.
2. See what is recorded in realtime without stopping.
3. Undo last recorded loop (not entire recorded midi) without stopping.
4. Replace old midi notes with new recorded which are close.
5. Edit newly recorded midi in PRV without stopping.
6. Some workaround for notes that should start at loop beginning, but was recorded close to the end of it (some smart algorithm to handle it)
7. Some other nice features?
Other related threads:
http://forum.cakewalk.com/Is-it-possible-to-loop-record-MIDI-with-Overdub-m3057688.aspx
http://forum.cakewalk.com/Why-does-Cakewalk-refuse-to-update-highly-outdated-midi-record-feature-m3266982.aspx
http://forum.cakewalk.com/Auto-merge-of-Midi-when-loop-recording-m3147500.aspx

I should chime in here as well. The integration of the Step Sequencer to PRV for this functionality would be nice for loop recording/layering/replacement. The "trigger" to replace or leave an event on each pass is really all that is required to achieve this.

I would like this feature (could find lots of uses for it), but I would also like to be able to toggle it on and off in the preferences window.  Would make life a lot easier in some situations but not in EVERY situation.
Can we add a toggle for this? 

arlen2133
I would like this feature (could find lots of uses for it), but I would also like to be able to toggle it on and off in the preferences window.  Would make life a lot easier in some situations but not in EVERY situation.
Can we add a toggle for this? 

I think the word "mode" means that I suppose it as separate mode from current "Sound on Sound" and "Overwrite" modes, something like this.

I can go for that Adq... MODE sounds a bit more "professional"...