I don't really think there's ever a point unless you become a monopoly like WWE was bc people still want some kinda confrontation so that they can pick their sides lol it just devalues both shows usually tho, even when done extremely well.
I’ll be honest the first one was great in the first few months. Than they tinkered with it only like 4 months in and I didn’t care as much for the roster changes and the title changes, but it still mostly ran like a legit split.
Once 2004 came around and they did annual drafts, I think you killed the concept. You should only move one two people a year in my opinion to keep the dies if brands as a legit concept. But even then 2005-2007 still had some uniqueness to each show, by 2009 that was gone.
Like you said, just devalued both shows for no reason. If nothing is different but the talent working, just end the split and do what Tony does. Use talent only once per show, but rotate which shows they work per week.
The biggest issue was the cuts too so the rosters got thin. Not large enough to justify two of them separately.