"Why do I feel so"
How fitting that this is repeated often.
You could say what she saw was just that... JAW-DROPPING!
You just reminded me of one of the possible many ponies Tirek absorbed the power of (temporarily). No wonder his physical attacks were packing quite the punch (yes, other Earth Ponies helped in this too, but Maud contributing to that strength is worth noting).
It was kinda nice to see a different twist on what Cadence noticed in Three's A Crowd. Discord THEN didn't really consider much of what Twilight was doing was for his sake really (after all, he only did that to annoy her day). In a different context, Discord really knows now Twilight really has his back.
You should've said "sliced bread is on par with mlp?" for greater effect
All the important set-ups (Ponyville representatives and Relay team) resolved with enough screentime to think there might be more. Maybe the next one, when it comes to Ponyville hosting it ;)
A giant spiky block of ice falling to the ground isn't "threatening"? And the pegasi that are just helping to slow it down and redirect it may not have been able to keep it up/pull it off well enough to give everyone a chance to evacuate. Plus it'd leave quite the damage either way.
Spike did more than just get rid of a threat. It certainly saved the Crystal Empire for needing to fix up a mess of structural damage and possible casualties in the event it showered ice shrapnel as it breaks on impact. It wouldn't likely just sit in the middle of the field (if they even managed to correct its trajectory).
Regarding Twilight's timing, it was mainly because she hasn't seen Spike and the Games are ending without him in sight. Though I agree you kinda expected something to happen to give Spike a redemption scene.
And it's possible she was exempt from it too, and was probably just about to use some to help when Spike took action.
Did you not notice Celestia and Luna go up to the clouds alongside all the pegasi that did? Because I'm sure you missed that...