Twas’ a time when Hamon was the bread and butter of Kaleos decks. The reason you don’t see it much now is because of the removal heavy meta. Here’s my analysis of Hamon Bladeseeker vs The World™:
The obvious killer of Hamon in my opinion. Enfeeble and Aspect of the Wolf completely trivialize your awesome 5 mana slammer for 3 and 1 mana respectively. And even if they don’t have those, you can have fun while they Frigid Corona or Flash Freeze your Hamon and have her play double agent on you. If Vanar wasn’t so oppressive both with their cards and in the meta, Hamon would see much more play. Rating: 1 / 5
Actually probably going to be one of the better matchups for Hamon. This is unfortunately just in theory though, I haven’t had much opportunity to test out Hamon vs. Magmar. On paper, the only thing they have to get rid of Hamon easily is Thumping Wave. On an empty board, Natural Selection can work but otherwise Hamon will probably always have the highest attack. Rating: 3 / 5
Beats up Tempo Argeon and sends him home with a wedgie. Lyonar has almost no answers to Hamon as a whole. Zir’an sometimes plays Martyrdom however, so that’s something to watch out for. Even then, however, that’s their only “clean” answer, and it’ll give you 8 HP back. Rating: 5 / 5
Due to the meta shift, Onyx Bear Seal is seen much more and Songhai and thus Hamon is less effective. However, If you can force 1-2 OBS out of your opponent before playing Hamon, she is almost guaranteed to stick as 3 OBS is an anomaly in most decks. Rating: 4 / 5
Fun fact: I used to consider Cassyva an automatic win if I drew the Hamon-Zendo combo before Punish came out. Dark Transformation (which I have never seen played since Rise of the Bloodborn came out) was the only Cassyva answer to Hamon. In Lilithe, you see Ritual Banishing but that’s a somewhat cumbersome play. Now with Punish to think about, it’s harder sell. Still, the amount of answers in Abyssian is limited and can be avoided. Rating: 2.5 - 3 / 5
Another one of those potential auto wins with the Hamon-Zendo combo. Before, you typically would play Hamon out of reach and hard mulligan for Juxta or MDS as you had to play around Entropic Decay. Now, that’s kind of irrelevant as Vet has the new and improved Blood of Air. I’d lean towards this being one of the best matchups for Hamon as if played on curve your opponent will be spending his entire turn dealing with it, and if ramped out via. mana tiles they have literally 0 clean answers for it. Rating: 4.5/5
Hamon’s ability is pretty neat, all things considered. You’re paying one less mana for a 8/8 (see: Stormmetal Golem) but it slowly kills you. 2 HP is the equivalent of one general attack which, in some matchups, can be the difference between life or death. But if your Hamon sticks and you can position it and your general properly, you can maximize on the huge benefits, namely, 8 damage to the face and a potential 16 damage Grandmaster Zendo combo.
On a side note, during the Race to S-Rank (Nov 30th 2016 - Dec 1st, 2016) we saw GrincherZ utilize Hamon Bladeseeker in a Midrange Reva deck. This was of course before the latest two expansions, but there may be some unexplored territory there.
Verdict:
Hamon Bladeseeker is, generally speaking, still a very good card, but the current rulers in the meta (Vanar and Magmar) prevent it from seeing too much play. Should the tides shift, you should expect to see Hamon rise once again.