The reason the twizzles are split in short series in Chaplin is that P&B chose the 3 piece twizzle series to earn a level 4 twizzle. The Shibutanis make the same choice. Their alternative is to do something that is a hard entry to the twizzle, like jumping into the first series. The 3 part twizzle was a good choice for P&B because it minimizes the fact that the direction of twizzle in the second group is significantly worse for Bourzat than the first and third group, and the judges always remember best what they saw most recently.
I agree that twizzles suit some programs better than others-waltzes, folk dances.
When you mention twizzles are inappropriate for cha cha, you are right. However, IMO, cha cha is a bad choice for ice dancing period. The basic dance involves a forward step, a retrograde step, followed by 3 staccato steps (cha cha cha). The staccato steps are apt not to be on edges, because they are too quick, and the retrograde looks wrong even if you do it.
However, next year's short dances only require the rhumba and the cha cha as pattern dances. Other Latin rhythms can be used for the rest of the dance (but not tango). Salsa or samba and twizzles would go together very well, I think, and if the skaters are wise, that's what they will do. Cumbia would work well too, but I'm not sure whether it is allowed.