A more realizable variation on my previous idea could be to make 4 shorter seasons of 13 installments each (instead of 26), with each season opener made as a full-length (1h30m) feature film for theatrical release that would tell the main story arc of each part (rather than just its beginning, so that someone watching only the theatrical releases would still get a decent picture of the whole story arc of the saga). Each season of the weekly series, composed of 7 installments of regular 30-min episodes intertwined with 6 installments of two short 15-min episodes each (for a total of 19 episodes per 13-week season), would serve to flesh out the secondary themes and plots that the feature film would've merely hinted at (for example, in the first season feature we'd see the Qadians joining ranks with Randor and hear about some characters being Gars, whereas some weekly episode would take us to explore the land and background of the Qadians and another to visit Anwat Gar).
The tetralogy of feature-length theatrical releases would serve to spark and maintain the general public awareness and interest in the franchise (which would otherwise be much more difficult with only a Cartoon Network TV series, as happened with the MYP series which many people never even heard about). And since all the audiovisual material for the weekly series and feature films would be stylistically consistent and rooted on the MotU Classics designs and canon, each season debut would be accompanied by a retail release of the relevant MotUC characters (He-Man, Skeletor, and the Heroic and Evil Warriors for the first season; She-Ra, Hordak, the Great Rebellion and the Evil Horde for the second; King Grayskull, He-Ro and the Snakemen for the third; and the Galactic Protectors and Space Mutants for the fourth), with the new Mattel development budgets devoted to adding the playsets, diorama accessories and vehicles that the line is so far missing.
This approach would allow Mattel to leverage the investment they've already poured into the development of the MotU Classics line (they wouldn't need to develop a second toy line based on a different live-action movie style and the likenesses of its actors, which moreover would compete with—and probably kill—the MotUC line). It would also allow the weekly series to "reuse" the CGI material developed for the movies (therefore cutting down the overall production costs and thus making it more likely to see the full saga materialized), since they would only need to 3D-model the main landscapes and characters once, and their reuse wouldn't feel cheap (unlike the stock-animation approach of the Filmation series), because once you have a computer model, you can easily render it in many different ways with relatively minimal effort (e.g., once you've modelled the Royal Palace, you can render it using different angle, distance and lighting parameters to obtain very different-looking perspectives of it at different times of the day, with little more than a click of the mouse).