During flood attack the network is in survival mode. Nukes are flying and we need to take shelter and survive long enough for the attackers to run out of ammo. We should certainly not be concerned about not being able to walk the dog in that time. As long as network does not break and there is as little fallout as possible, the attack should be considered a failure. But yes, during attack users need to adapt to be able to still transact if they absolutely need to.

Surcharge mechanism will be triggered as early as first block from the start of flood attack even on default setting (depends mainly on size of transactions), but it won't trigger in normal burst-of-activity situations. Even with the mechanism activating, it will take time for the attackers to be affected - their RC levels need to drop significantly before they start to be locked out, or the mempool needs to bloat to scale up the surcharge. In the latter case everyone weaker than the attackers will be locked out. Even when attackers start to be affected, the mechanism just lowers the intensity of the attack, so it is easier to survive.

I think the ideal system would let you see the pending transactions related to any account on their account history page.

It makes no sense to ever implement something like that in Hive. Outside of deliberate attacks, short lived burst-of-activity or network congestion all transactions are included in the nearest block and they even become final before you could refresh history page.

Looking at your concerns I came up with a harassment type of attack that could probably be performed by a single whale :o) It wouldn't affect the network safety, but could negatively impact user experience. Unfortunately to test it (and also potential countermeasure) I'd need to make a lot of changes to the tools I have and I'm busy with other things.