When importing MIDI from another application, notes can overlap. Editing the notes, either in the Piano Roll view or the Notation view, can be difficult. If Sonar had the capability to separate overlapped notes into separate lanes - not for the entire track, because the overlaps might be too numerous to display - but over a limited time range of starting times, it would be much easier to fix the overlap issues. The .cal procedure to fix the doesn't work well; manual editing is required.

Are you taking about Type 0 MIDI files where all parts are in one track, distinguished by event channels? In that case, you can easily break them out using Select > By Filter or CAL ('Split Channels to Tracks' or somesuch).
 
Or do these tracks have duplicate notes on the same channel for some reason? If they can't be distinguished by a consistently different range of durations, velocities or starting tick values, the Event List view - or writing your own CAL - may be your only option.
 
I can't see the Bakers spending time on a feature to de-fubar a badly recorded/sequenced/edited MIDI file. This kind of problem is better addressed at the source - the loose nut behind the wheel.