I also think the engine is difficult here for the mentioned reasons, but if I'm forced to play it I would like the Advisor better. Point is that with Consp/Treasury, you play a cantrip engine that doesn't increase handsize. And you don't have trashing, and 12+x stop cards in your deck that interupt the Cantrips (7 Copper, 3 Estates, 2 Ironworks, x Provinces). 1 Caravan increases your handsize by 1/2 (you can only play it every other turn at best), 1 Advisor by 2. Without trashing, you need every bit of handsize you can get. You can gain the higher valued discarded cards by the Consp/Treasury. This is of course still not optimal, but should work out better.
But the problems still remain, it's a kind of slow build up, and you don't have anything real to do with the engine you build. But given a say Woodcutter on the board for at least double Provinces, I would take maybe 2 Caravans for consitency and otherwise prefer the Advisor.
full disclosure: I've never played wth Advisor
...