Well, two days later, and neither my wife nor I have brought it up. Show kind of dead to us; it did finish more weakly than it deserved.
The white tulip references one of the better episodes in the series, a good one with Peter Weller as a scientist who basically figures out how to loop/reset time, but also gives an interesting look at fate, faith, and how they can interact with each other. That was a fabulous episode, but to have it act as a springboard for the final episode, which is... pale, in comparison, is sad.
Olivia's "big moment" was anticlimactic. When I saw the whole city skyline go dark little by little, I thought "IT IS ON!" ...and then spoiler (click to show/hide)
she throws a truck at the guy who can dodge bullets, Captain Windmark. I thought she would just make him explode or melt. Even the truck would have been better, if there could have been a moment showing that she was psychically holding him in place while she moved the truck.
Things I liked:
- Using the backlog of Fringe case evidence lockers (Walter's "Batcave souvenirs") as ammo in the fight against the Observers.
- September was cool; the actor playing him did a fine job adapting the Observer character to the changes humanity had wrought in him.
- Walter finally seemed well-integrated between his two personalities: whimsical but broken, and ruthless, god-complex
- Several bittersweet, "yes, this is the end of the series" moments.
Overall, though, the series shifted too many times, and it was ultimately hard to track who had done what to whom in which timeline. At first, I enjoyed the shift from s1's "Massive Dynamic is the enemy" to s2's "Walternate is the Enemy," but when we were still seeing shapeshifters after the truce, and they brought back David Robert Jones a few times too many... and this last shift over to the future, it felt less like risk-taking and more like indecision.
In the end, it was a good show, I liked it quite a bit, but I wish there had been more consistency over its run, which would have given it a chance of a stronger resolution in the end.
...And if the Observers have been erased from existence, wouldn't Walter and other-side's Peter drowned in the river when September was not there to intervene? Or, without September's accidentally being spotted, wouldn't our-side's Peter never have died?
It's just casual time-travel "lite" storytelling, so I shouldn't let it bother me, I guess.