The problem is it's possible to lose missions you've fulfilled the criteria for, meaning if you waited on the 'have 150 opinion with 2 allies' mission, and one of those allies rivals you since you're the only possible rival, suddenly you just got locked off from the rest of the tree, and if you're playing in a region with a ton of TI, well, you could be shit outta luck. I suppose you could chalk it up to the player's fault for not realizing they were going to get rivaled, but I personally feel if you fulfill the criteria, you should be able to get your reward, regardless of future circumstances. Obviously this isn't really a mission that matters much at all and is usually pretty trivial to re-fulfill, but there are other missions, like occupying Paris, where this can be an actual issue.
