@Solipsist
I brought it up because you just went into making the game longer, which in a pen and paper isn't an issue. this is an issue with mechanics that happen instantly but need to be played out, splitting parties this way effectively makes the game a solo/half group game, the logistics of splitting, at least if any info will be said in that part of the game that may help the other party, means they are no longer even present or else they will ultimately know things they shouldn't. I would say most people who plated pen and paper probably encountered a large scale battle that 'split the party' but on a far smaller scale.
with computers and not needing to be physically present, splitting the party like that could work better, but its VERY hard to split the party in a way that makes sense for a long term scenario without turning player characters into npcs.
as for spoony, there are probably other people i could reference for a party split, but I don't really follow people telling d&d stories in great detail, and with as far as he fell, his content at its peak was some of the most memorable online content i can think of.