Worthy of Inspiration:

• Black Cat - Scratchin' for 2 all game
• Daredevil - THW 3 + 1 Damage Splash is tasty
• Hulk - HULK SMASH MOAR
• Jessica Jones - Punch 3 + Conditional GODTHWART
• Tigra - More lethal Tigra = Tigra around longer
• Vision - Yes. Just yes.
• Falcon - 3/3 is a strong statline.
• Spider-Woman - 3/3 again. 2 HP is low, but with Get Ready she can be a 6 ATK/THW + Confuse burst.

Probably Not Worth Inspiring:

• Black Widow - 2 health and you'll be exhausting for her ability.
• Hawkeye - there's an argument for it, but nah. 2/2 isn't worth it.
• Luke Cage - most of the time you're going to just tank with him twice.
• Maria Hill - 2 HP, and you want to chump-block with her for Make the Call.
• Mockingbird - she's a flashbang and a block.
• Nick Fury - seriously? YOU'RE going to inspire Nick Fury? He's going to leave halfway through your speech.
• Shuri - 2 HP, Tutor and Block.
• War Machine - If you actually installed Rhodey, he's probably skeeting Ultron Drones for you.
• Hellcat - She'll lose Inspired when she does what she does. Situationally might be worth it for the THW.

The value of this card is based on how many times you can use it. It is a total waste if you only use it once before the ally dies, but adequate if you can use it twice, and potentially rather efficient if you can use it more times. Here are some ways the card can be used:

1. The simplest default use is to pick a hero with 3 hit points and Inspire them. You will get to use the Inspired bonus for 2-3 points of extra thwart or attack before the ally goes down. This is a decent return on your investment, an OK play when you have nothing better to do, but not good enough to be the reason you put the card in the deck. This card is cumbersome to use since you need a healthy ally you can leave alive for multiple turns in order to get the payoff. Since you often aren’t in a good position to play it, when you are in a good position you want it to be an exciting, strong play. 2-3 uses is reasonably effective but not exciting.
2. I generally feel the bread and butter of this card is in a deck with First Aid (or an ally with Med Team). You find some ally with 3+ health and 2 thwart, Inspire them, and then repeatedly thwart with them and heal them back up. It eats up an ally slot but is a very efficient way to remove a ton of threat over time.
3. Sort of a compromise is to Inspire an ally with a lot of hit points, like U.S. Agent. If you can Inspire him, thwart with him 4 times, and chump block with him, then your small investment in Inspire will have removed a respectable 4 extra threat. Or you can Inspire Goliath, thwart 3 times, then get a bonus on his glorious finishing blow. Or you can use a card like Team Training to give your characters extra hit points and thus make Inspired more effective.
4. A different use for Inspire is as a part of certain combo decks. With a Teamwork deck, for instance, how can you resist playing Inspire on The Vision to get the highest bonus possible on your Teamwork action?