>>6350683I'm sure he could be revived as his essence still lives on in his children, particularly Raven. Gods and Devils are metaphysical beings more than anything, so they aren't really subject to the same rules mere mortals might be.
As for whether or not he'd be a threat, I'd say his malicious intent and assumed grudge against us marks him as one, even if we've eclipsed him in power several times over by now.
Besides, all Trigon would need to do is find
or create a new champion. There are plenty of absurdly strong beings that he'd be able to tempt into his service or outright enslave.