Where do you see "Arc" system? Or are you just using that term because WotC had an Arc system previously?
Really, the idea is that the game is "all superheros", so while it would be cool to call it simply "Marvel", doing so would prevent creating a compatible "DC" game. So, the game is "Vs. System" and the "Marvel" game and the "DC" game will both use the "Vs. System" engine.
So it's sort of like what WotC did with the Arc system, but not really. WotC built several games that were meant as stand-alone, but could be played together. We are designing everything as a single game, but that can be played as stand-alone.
The game is actually pretty fun. I'll let everyone form their own opinion once it comes out (sometime next month).
As far as Yu-Gi-Oh dying, there are reasons it would appear so, but the truth of the matter is that we get FAR more players at a Yu-Gi-Oh qualifier than at any Magic qualifier still. There are certain reasons why it appears as if Yu-Gi-Oh is dying. Things which can cause problems if not corrected, but we are obviously working with Konami to avoid that from happening. If there are any Yu-Gi-Oh fans out there, expect to see some reasonably exciting stuff in the near future.