Re: If the Guauntlet fits, you must admit .... it's time for Thanos!
When thinking about it both of you guys have a point. While the scale of the threat does get bigger with each installment, giving the right story almost any character can be made into a bigger threat than the previous one. Take the Dark Knight Trilogy for example. It can be said arguably that the scale of threat level can go Bane>Joker>Ras Al Guhl or Joker>Bane>Ras Al Guhl depending on the right storytelling. Yet, Nolan went Scarecrow/Ras>Joker>Bane.
With that being said Whedon can definitely make the scale of Avengers villains work like this Loki/Chituri army>Thanos>Ultron.
Even in video games the biggest and baddest isn't always the final boss.
1) Man of Steel 2) Thor 2 3) The Wolverine 4) Pacific Rim 5) Iron Man 3 6) Oblivion 7) Mortal Instruments: City of Bones 8) Ender's Game 9) Beautiful Creatures 10) After Earth