Who is the best Tactics hero in the card pool right now?
Oh, sure, Boromir is the cornerstone of the most broken deck on the block, and he's amazing, but that's as much about how broken Gondorian Fire / Blood of Númenor / Steward of Gondor are as Boromir himself. Aragorn combines a fantastic global debuff with an incredibly powerful triggered ability. Mablung can reliably net two resources a turn, (and, with a bit of work, three or more), in a sphere that has no other built-in means of accelerating its economy. And with a threat three full points lower than any other Tactics hero, Merry occupies a deckbuilding space all by himself.
But overlooked next to that quartet is humble Háma, who developed an early reputation as "that guy who recycles Feint every round". I mean, sure, Feint is an awesome card and the ability to play it over and over is very powerful. But Háma is as powerful as the Tactics event cards, and right now the Tactics events cards are unbelievable. Háma gives you unlimited access to readying effects (Behind Strong Walls, Boomed and Trumpeted, Hold Your Ground!), incredible card draw (Foe-hammer), and direct damage (Skyward Volley, Rain of Arrows, Pursuing the Enemy, Hail of Stones, Goblin-cleaver). He lets you completely break the order of combat and attack out of phase (Quick Strike, Hands Upon the Bow). He lets you recur game-turning global effects, (Charge of the Rohirrim, Forth Eorlingas!, Horn's Cry, Hour of Wrath, The Hammer-stroke, Thicket of Spears). Hell, if he wants to, Háma can even turn Tactics into a questing powerhouse with Trained for War.
And when I say "unlimited", I mean unlimited. While recursion in this game is mostly limited to a series of rare one-off events, Háma's ability is endlessly repeatable. If you pair him with an Elven-light and some Spirit resources, that becomes literally endless; you could have a game that lasted a million rounds and Háma could enable you to play the same Tactics event in every single one of them.
And he hardly sacrifices everything to get such an amazing ability. He ties for the second-best attack of any hero and the second-lowest threat in the sphere. His Rohan trait isn't quite Silvan, but it's still one of the more useful, more-synergized ones on the block.
Usually, the "top-tier" heroes are the ones who give you more cards, more resources, or more actions. Háma doesn't fit in any of those three major archetypes, mostly because he's an archetype to himself. There is no "infinite recursion" bucket, there is only Háma. He doesn't just make existing decks run better, he enables decks that couldn't exist without him. I'm not sure if he's the best Tactics hero, per se. But he's far and away my favorite.