While there is a slight excuse that players have comparing this card to United We Stand since more the half the heroes were Avengers when this box came out, it is now an exceptionally flawed comparison. Not only does it miss the fact that it's only on Skirmish 3 mode that United We Stand gives you 3 health across 3 characters the entire game (on expert, most of the game is spent on Stage II, not III), it ignores that retaliation would deal extra damage to each of your allies attacking on their own, non-avengers can utilize this card just fine, and that there are lots of leadership decks that boost the hero's attack, so this allows you to pull double duty of keeping your allies out longer and utilizing those turns where hero is packing higher levels of attack.
Once again, the thinkers out thought themselves on this one.
In the current environment of Sentinels capturing your chump blockers, Infinites getting stronger when you recklessly throw away allies, and way more Villains utilizing overkill so there are no guarantees that your allies will even prevent much damage. There is also allies like Colossus, Wonder Man, Blade, Giant-Man, Cannonball, Drax, etc, etc, etc, that have stipulations about there attacks that might not be met each turn but cards like this by-pass that.
This card was always better then branded, and if someone is keeping it in the back of their binder, they might consider breaking it out to allow themselves more ways to get around ally limitations and villain/minion defenses then they were thinking.