I see no bigger point in just adding “a rhythm”, and it would absolutely not be useful in the Chord track itself, because generally every track, with different instruments attached, has different rhythm (while the Chord track is for all tracks).
But what I WOULD like to see is a separate VSTi that works like Catanya, i.e. a “Chord Pattern Arpeggiator”. It works like this:
It takes an incoming chord (3 notes) and then make that chord come alive by making it into an arpeggiator pattern using the chord notes, from a preset pattern. In addition to the current octave, also the chord notes 1 octave up and 1 octave down can be used, totally using 9 chord notes in a preset arpeggiator pattern. (If developed by Steinberg, maybe also 4 note chords should be possible). You can also set different velocities in the preset patterns, giving different grooves.
So this means every track could be routed to a different preset pattern, and the incoming chord notes could not only have different rhythm for the chords added, but these chords could also be made into arpeggiator patterns, playing broken chords and whatever you want using the chord notes. The output is routed to separate tracks and can be recorded, and then treated further.
See here for a demo of how this works:
This fits very nicely with the new Chord paradigm of Cubase, and is a logic and natural continuation of this. A very creative and useful tool. Of course, you could just buy Catanya to have this functionality
But it is so useful so it could be good for Steinberg to have such a tool developed in-house and have full control of it, and maybe build upon it further (*).
(*) Edit: several ideas to be found in my following post, e.g. automation of pattern changes.