So... yeah, that's one. Can you defend the others from 'situational, but strong'?
It depends on what you define as situational. If you consider all Daily powers are situational because they are once per day, then how could one have a broken Daily power at all?
I ran a 4th level fight with a BBEG that did 2d8+5 damage, two attacks per round, if both attacks hit, then an additional 1d6+1 damage.
Astral Condemnation which works regardless of whether it hit that foe stopped 9 points of damage per damage roll.
So, instead of doing 14 average points of damage per attack and 32 average points if both hit, the BBEG was neutered down to 5 average points of damage and 10 average points if both hit.
That's one third. Yes, I consider neutering the BBEG to 1/3rd damage with a power that does not even require a to hit roll to be broken.
This isn't just strong. It's turning the BBEG into a Standard monster threat, just one with a lot of hit points. He's no longer a BBEG. At 4th level, that could be as much 100 hits points of the equivalent of free healing or ~8 healing surges.
Granted, there is the traditional workaround for this power. Stun the Cleric or knock him unconscious so that he cannot sustain it.
How would you as a player feel if your Striker started doing 1/3rd average damage automatically without a to hit roll? If the DM said "I'm sorry, the monster just nerfed your PC. And, there are several such monsters in this dungeon, so expect to have it cast on your again tomorrow.".
One definition of broken could be that any power if used on the PCs, would make them bitch and moan to the point that they might consider quitting. Another definition would be any single power that drops an N+3 encounter down to an N+1 encounter is broken.
If I'm in a dungeon, I expect to run into a potent Elite or Solo at some point in time. So, I don't consider this Daily to be situational either. I expect it to be used most days. That's pretty typical for a Daily and not situational at all.