It's normal to feel underwhelmed by Larcade since Mashima did build him up as the third strongest Spriggan after August and Irene. In that regard, Larcade didn't really live up to his expectations. But hype and portrayal aside, Larcade's abilities were objectively more powerful than Bloodman as at one point, he did actually managed to floor a wide group of people across multiple different locations. This group of people included Gildarts and Laxus. Even the likes of Zeref and Irene, though not floored, were being affected and feeling distressed like as though they were nursing headaches. I know you can bite your own tongue hard enough to bypass the spell, however we should not assume that just because Kagura could think up of that as a solution, somehow every other character also possess the same school of thoughts as her.
Bloodman's walking genocide MBP wouldn't work since Larcade is also an Etherious who uses curse. MBP should not be fatal against him. I'm more inclined to believe that Larcade's curse would work on Bloodman. Yes, I know Bloodman is an anomaly and his physiology is different than a regular person. However, his character clearly has an ego who possess his own personality and will. It won't come off as really surprising to me if has desires too. And if he does, Larcade should bring him down easily. Larcade also has better reflexes and durability feats than Bloodman. Voted for Larcade.