I voted alternate torso for the standard option that they've done before and they'll probably do...but here's my preferred and probably undoable option:
They can't do very many unique sculpts, which is why it took so long to get to Ram Man. We don't have many that need it, honestly. Extendar might be one, and some might say Rio Blast, but I think we can get along with attachable items for him. Blast Attak...well, here's why my idea is probably undoable - they stick REAL close to this "no action figures" business. I think they should forget it with Blast Attak and give him just a openable torso (not a separate one, but just one torso that opens up) - AND - if they were willing to go that far, I don't see why the torso can't bust open with the press of a button.
So yeah, they won't do that, but I think that's how he should be done. The inner workings for an opening torso with a button to release it shouldn't get in the way of two slots for fully functioning arms, so you wouldn't be missing anything but the stomach crunch articulation, and it was totally worth it to get rid of it for Roboto. I don't see why Blast Attak should suffer the loss of his feature when Roboto didn't have to.
And let me say that this is coming from no nostalgia; I never had this guy and I've never even held him or seen him in person. I just think he's cool and his feature is just as interesting as Roboto's, so he deserves to have his intact as well.