Skipping Ten in the numbering for a personal intricacy. With the advent of Magneto as a deploy, I've come to see the expansion of lockbox and special operation characters role and necessity as an unavoidable fate. But, to keep things so simple with a lockbox character every spec op, every PVP season, it will be boring.
So I came to think of the possibilities of using other game features to aquire lockboxes, in a similar way to Covert Tasks offering miniature spec ops. The most salient idea was the Incursions, which could offer interdimensional variants of heroes, or perhaps alternative outfits, based on other Earth versions of the characters, and others characters with dimension related origins.
Characters such Nocturne, the Daughter of Nightcrawler and Scarlet Witch, Lyra, daughter of Hulk and Thundra, May Parker, Spider-girl of the future.
With getting Daily Mission, that seems to have ended up being the result they decided with, but I'm sure they'll want to revamp Incursions to make them interesting at some point, few things do that more then getting characters.