>>9981176Mega was a plastic building block company long before Halo, it is tooled up and experienced with the format and even has a landmark legal victory over Lego under its belt, why change tack? Would imagine it's one of the reasons Mattel acquired them, to get a share of the PBB market and compete with Lego et al.
Mega did try a weird sub-theme in 2012 called Metal Series, was a smaller scale diecast line of Halo vehicles and figs with their brickbuilt designs, guess it was intended to compete with a similarly micro-scale Halo line from another brand around the same time. Needless to say it flopped and was quietly ended after just one wave.
The figures are certainly one of the great draws of the line, but don't underestimate the attraction of having brickbuilt sets of Halo and other favorite themes, all intercompatible with Lego and other brands and (until recently anyway) for cheaper than Lego. When I first got into the line I was just as thrilled by having buildable Warthogs, Banshees, Pelicans and the like as I was with the mini action figures that were in such contrast to the venerable Lego minifig. By making a considerable percentage of their offerings blind bags, "Heroes" and troop packs Mega definitely is aware of their popularity but I expect they'd be less so if they didn't have some vehicles and playsets to go along with them.
If anything I'd imagine another company might try to compete with Mega on this level with the kind of toy line you're suggesting, but I'm skeptical of that happening. Halo is faltering, by the time that hypothetical line is conceived, R&Ded, approved, tooled up for and finally put out on shelves it'll be Mega's GoT line all over again, way too late.