I don't know how big those toys that aren't Transformers that you're talking about are, but the wording on the rumour is ambiguous at best. "Box are Metroplex sized" is what it says, which could just mean it comes in a box the same size as Metroplex's. At best, it tells us nothing about the nature of the actual toy. According to the rumour, the source doesn't even know how many toys will be included. If it's six rather than five, as with G1 Devastator, then the extra bot could easily bulk up the size to be comparable with Metroplex, if not at exactly the same height. If it ends up being around the size of supreme Unicron, for instance, then it would still be in the ballpark of Metroplex.