Paul's Writings Underpin Western Thought

[Angrboda]

I didn't see what Brian offered..but...Constantine was a reformer by necessity, the imperial cult had withered (Julian called-Apostate after him would not be able to revive it) and he needed a new hook on both the plebs and the military.  He spent his time as emperor consolidating his power and far be it from me to say that the elderly Constantine.... on his deathbed...... didn't deeply truly believe...but...if he did, it was still damned convenient to the diminished seat of the roman emperor at the time.  That particular throne had always been based on divine providence....but the scheme of divinity was changing.

I don't doubt that he might have truly believed. What I doubt is that such explanations as yours or Brian's have any firm basis in fact and evidence. They're like the apologist dodge of "it could have happened" that way. The question is not could it happen that way, but did it happen that way. If there were some official recognition of such an explanation, I suspect I'd have heard that before, instead of the usual trash about Constantine wanting to curry favor with a small and unrepresentative religious minority. So your explanation while plausible, is lacking the proverbial smoking gun which would clinch it.