Hey Reynard,
I've been enjoying your weekly one million threads, and I had an idea for "one million adventures", using the quest seeds in DMG and some motives, maybe a complication or two...
One Million Adventures
What you've got there is a "Adventure Starter Table", because your first table will lead you only to one other subtable, which then has a complication. If I were to write a "One Million Adventures" table -- which I will; am, even, but it's really complex and difficult -- I would use something like the following categories:
Adventure Type (McGuffin Hunt, Slay!, Save the Innocent, etc...)
"Quest Giver"
Gettin There is Half the Fun (a table saying what kind of environment/terrain the PCs have to move through to get to...)
Adventure Location (subtables for different dungeon types, city neighborhoods, etc...)
Stock Enemies (by rough type: undead, humanoids, etc...)
BBEG
and, as you said, Complications (ally is really enemy, enemy is really ally, third party intrusion, etc...)
But a table for the purpose of jogging yur imagination on how to get the PCs intersted or involved isn't a terrible idea. usually, though, players will either take the bait or they won't and adventure hooks are best designed for specific groups because as the DM you know what's going to get them motivated. It isn't railraoding, it's behavior modification!