Dear Mega,
First I'd Iike to thank-you for the Masters of the Universe line, which my son absolutely fell in love with. It was nice to see my son find enjoyment in a genre from my youth, but sadly very few places carry the items now, nor within the price range of what I feel a toy should cost. Yet on reflections, I didn't think that should prevent me from reaching out to make a few suggestions.
Rather then a He-Man vs Best man combination pack, I think that you would be hard pressed to keep a He-Man & Battlecat or Skeletor & Panthor pack on the shelf, especially if they had different armor schemes that your creative teams might pursue to give it a new twist. I know that these have recently been added to expansion sets, but most kids will be hard pressed to collect them from these sets at the prices they are going for. A Prince Adam and Cringer might work too.
Next I thought the Battle for Eternia five figure set was awesome! It let kids get all the released figures at once. I think you could benefit from creating an Eternia Villains set, which might have a Skeletor variant, Mer-man, Trap Jaw, Triclops, and a unique character like Webstor.
The same could be said for an Eternia Heros set that featured a variant of He-Man, Ram Man, Man-E-Faces, MekaNeck, and the unique character like Buzz-Off or Orko. Or you might switch the unique hero and villain to the alternating set.
Needless to say you hit the Castle Grey Skull out of the park, and a Snake Mountain is hopefully in the works. Along with a much needed Battle Ram or Land Shark.
Which ever direction you choose to pursue, please know that I am grateful for the joy you brought my family, with not only being able to relive my youth, but see my son find the wonder in his imagination.