Yeah, I don't see Ruger designing anything around a P90 magazine, more like they'll come up with a 5.7 variant of the PC carbine that takes the same mags as the Ruger 57 just because a few fanboys will buy it, even tho at that point a budget AR would be a better choice.Wait a few years and Ruger will copy it with significant improvements because their engineering team seems to like to do that.
It was also somehow be beautiful or absolutely hideous like someone did the technical drawings with a dull crayon, because Ruger also does this and can't seem to stop alternating between ugly ducklings and swans.
I will admit the whole selling point to the 5.7 was the P90. If you were to take the 5.7 and slap it in an AR, the thing would have been a massive failure, so if Ruger is smart they won't make a PC in 5.7. If Ruger is gonna do anything they may as well copy Kel Tec and make a bullpup that uses the 57 mags because at least that would be a pretty small and light, yet superior rifle in 5.7 than that hideous P90 FN makes with the 16 inch barrel.