Just got the game and read the rules, and I was a little confused about the objective cards.
On page 3, it says that when you place or move a pawn into a purple space, you "draw the first three Objective cards and add them to your hand, then put any two Objective cards from your hand at the bottom of the pile."
On page 4, it says "Very Important! As soon as a player plays his Objective card, he immediately draws a new Objective card. A player cannot have more than 2 Objective cards in his hand. If a player already has 2 Objective cards when he has to draw a new one, he has to choose and keep only two and put the other at the bottom of the Objective cards deck."
So, in general, objective hand limit is 2, and the number of objectives you have will remain constant, since you always replace one you use. If you have 2 objectives already and you move into a new purple space, wouldn't it be true that you really are drawing 3 and then discarding 3?
(The only time you'd get to actually gain a new objective card is the very first time you settle a purple space, which increases you from your initial 1 objective to 2, and then you'll stay at 2 for the rest of the game. Is that correct?)
This just seems to make purple a little less beneficial than you might think, because it really mostly just gives you a chance to pick *different* objectives, not *additional* ones. But if you're working on achieving the objectives you have, how often is it actually useful to switch objectives mid-stream?
Normally you want to have 2 objectives in hand asap, which is the maximum and usually after getting the second one you renew only by completing objectives (Soon enough you can memorize all of them and anticipate potential future objectives during your moves).
But if you're stuck for whatever reason it's potentially a good move to refresh fully.
Origin main driver is objectives completion (because they are "indirect" which makes them efficient: you can Collect a hunting or straight token while completing an objective - e.g. group of pawns together - and ideally preparing for another potential one - 3 Tallest / 3 Largest / 3 x 2 in each Color are the classics, Technology sets and connected pawns come next).
IMO, this level of sub-optimization is what makes it very enjoyable for competitive gamers while remaining accessible to all players. At least it works for me.
Have fun playing,