Might not hurt adding some ratcheting — or we can call that Fills.
On some page we can use 7 pads to switch between the tracks, and then set trigger repeats per step.
That would take it further than traditional TR sequencing, and allow for more intricate rhythms.
And for setting length per row, I’d certainly consider hold+push to set the step range (so that pattern doesn’t have to necessarily start on step 1). If you think about it, that can be an easy two button press-way to shift between strong and weak accents: e.g you had a hi-hat pattern where all hits fall on a downbeat, you press 2-15, and then they all hit one step ahead.
Also maybe utilise a few pads as quick fill-in hotkeys (that would fill-in empty steps), with say, probability range of 25 to 100% in range of 25. Hold a 100% pad on a snare track and have a quick drum roll, or do the same for kick drum to spice up the rhythm.
