Anyway, for the proposed "analog" sequencer usecase, a dedicated implementation model would likely be more suitable.
At a programming level, it would imply an extension to the cursor advance engine, at an interface level at least a switch selecting between "legacy" and standard play mode of a track. Nice you proposed there!
Too bad the track clock specifiers cannot be addressed from events. Could have been fun!
Regarding legacy/standard play mode, the best option of course would be to not have any mode added to the system and find some standard way to implement steps with a variable size, but defaulting to the standard 12 ticks per step. That would mean however that a track no longer has a fixed size of 192 resolution ticks, but now depends on the accumulated sizes of each of the steps. Sounds kinda drastic, heh.