Agreed, any time you add in a merge point, you're just going to increase wait times for everyone.
Out of curiosity, where were the corrals? Where did they separate? DMP feels like one of the more basic, straight-forward Express lines, I'm having trouble picturing this.
Also, as dumb as this idea was, it sounds like long Express waits have been enough of an issue that the order has come from on high to fix them.
Only did the front 5 houses last night, but combined with reports here and on Reddit, I have a theory: once lines go up over 60, and especially 75, they begin throttling Express. Hellblock and Coven were posted 40 and 45, basically walk-ons with Express. Halloween was I believe 75, Express suddenly jumped to 30. This is all obviously speculation, but I'm thinking Ops is desperate to avoid triple digit wait times. Maybe that's the magic number that ruins GSATs or stops guests from entering a queue (further overwhelming the already busy streets and food booths). But Express waits seem to jump exponentially around that mark.