I would be fine either way with whether or not it triggers a mandatory reveal from Nullify or another Reverse Magic. My only concern is that things remain in the Counter Spell Step. I don't like time travel. It makes me queasy.
If you were to reword Reverse Magic so that it's owner takes control of the spell in question and THEN redirects it back to the caster, then a ruling stating that mandatory triggers apply would make sense. This would maintain the expected behavior of spells like Nullify, making the game easier to understand and learn.
However, leaving the wording the same or updating it to clarify that the owner redirects the spell and then takes control of it, thereby avoiding further mandatory triggers, allows for more tactical options during game play which I think enriches the experience. If I'm being honest, however, this is unintuitive. The question then seems, to me, are more tactical options with these spells worth a steeper learning curve?
*shrug* I don't know the answer to that. Either way though, things can and should stay in the Counter Spell Step.