One possible change of trajectory for Iran is that a military dictatorship replaces, finally, the nominally religious one, overtly casting aside the trappings of theocracy. The mullahs may be abstemious religious scholars intent on preparing/purifying themselves for the afterlife, but almost every other kind of person enjoys some pleasures of the flesh, for which it is necessary to be alive and preferable not to have to keep looking out for killjoy religious enforcers.
That Khamenei's son might have been selected as his father's replacement is a substantial step down in quality, as Khamenei was a (slight) step down from Khomenei. If the IRGC is fed up with or senses weakness in the religious leadership, the IRGC can take all of the power, if they choose.
The regime (how the government is structured and functions) might not really change much, but it's foreign policy might change a lot and reset conditions and terms of negotiations.