I don't think this card is playable by any stretch. Sure it costs 0 and can be used on any player even if you're in hero form, but it's still 1 card, and 1 card can do so much more than prevent 1 damage.
And with this, Victor Mancha is officially obsolete!
As long as your hero has at least 2 DEF, she can block most minions. But she obviously shines with even higher DEF. Build up your DEF enough, and she can start safely blocking the villain attacks. Obvious cards to include with her are Armored Vest, Defensive Conditioning and Innate Reflexes. Once she has 5-6 DEF, it will be extremely hard for the villain to damage her.
Use her with Hangar Bay to block multiple attacks each turn. Once you have your DEF maxed out, she can help you block for the table in multiplayer.
The only problem I see is that she has a weird anti-synergy with a lot of Protection decks in solo. If you're playing Protection and building your DEF, you usually want to take advantage of Unflappable for its card draw, but that's going to be harder if you're using Echo to block for you.
All that considered, its still 3ER. Assuming a base 2THW, this is a save-for-later 3THW (which is in be lower middle part of the cost efficiency for thwarts). However, with having a base 3 or 4 Thwart (Innate Perception, Heroic Conditioning), this cards becomes an expensive but worthy asset, if the above conditions dont mess with your deck and with your hero.
This is a really fun build-around card for Leadership. At face value, it makes the decision on what to do with your ally's last hit point much more interesting. Blocking a villain attack is usually more powerful than a basic thwart or attack, but with a +2 buff, the basic activation will often be better. There are many ways to build around it even more:
Tough statuses: An ally with 1 hp and a tough status can still activate with the buff without dying. Defensive Formation is probably the most efficient but only for Defender allies. Ready for Action works as well.
No consequential damage allies: Yondu, White Wolf, or Black Cat are allies that you can take down to 1 hp thanks to consequential damage from thwarting. Then repeatably attack at 1 hp without taking consequential. Mission Planning or Unified Strike can also do this for any allies, but less consistently.
Use the allies' power without activating: Teamwork and Mass Attack let you use your allies' stats without actually prompting consequential damage. In a multi-aspect deck or multiplayer team, As One!, Team Strike, or Mutant Peacekeepers function similarly.
"You weren't going to block anyway". Goliath or Last Stand give strong final activations but discard the ally. Thus losing the ability to block is hardly a downside. In a more general sense, high-stat allies like X-23 or Snowguard are likely to activate with every hit point already, so Righteous Purpose fits seamlessly.
I'm not sure if any of these strategies are overall stronger than typical ally swarms which block frequently, but I love the unique gameplay it provides. If you are planning to use your allies this way, you probably want a hero who can capably protect themself like Spider-Man, Colossus, Nightcrawler, or Luke Cage.
This card is kind of paradoxical for me. Normally the good thing about cards that generate resources is that you can play more cards each turn. But for Arrows, you're limited not only by resources but by how many times you can exhaust Hawkeye's Bow. So often I've had these sit on the table not being able to be used either because I didn't draw enough Arrows. Which again is the problem with Hawkeye - if you draw too few or too many Arrows, most of your hero kit does nothing.