First off, before jumping into ‘X era or zone would fit more into Aoe4’ please bear in mind this is not a discussion about the timeline or location. You could think about it as a scenario or campaign or game mode which wouldn’t necessarily exclude other possible scenarios or classic game modes. It’s just a ‘what if’ debate.
Now, it’s interesting that these wars haven’t been depicted in any big video games, AoE series included, (I was living under the impression that Total War: Thrones of Britannia was focused on these, but it’s actually set way before that) and I think they’d provide a good foundation to work on. After all, these are the wars that inspired George RR Martin into writing Game of Thrones, and we do have Tywin Lannister narrating the trailer 
So, we have lots of belligerents and leaders in a 32-year war of tactical diplomacy, betrayal, cowardice, idleness, chaos, corruption and so on, things which made me think would provide an ideal foundation for something AOE4 could come up with, a game of thrones. We also have external forces like France, Burgundy, Scotland which could join into the fray.
While the gameplay would feature medieval warfare in this particular case, it would require the development of a more advanced diplomacy system and also a dynamic campaign style in my vision. And these are some of the areas where I always thought they could vastly improve on and come up with something better.
So, imagine you’d start this particular Wars of the Roses campaign or scenario where you’d fight battles one after the other and manage alliances, but the outcome would never be the same. Therefore, instead of simply clicking the next predesignated battle on a map or menu, you’d find out that you now had to defend House of York at Warwick Castle because you didn’t offer support to the Lancasters in a previous battle, or that your previously secured ally turned weapons against you unexpectedly after being bribed - so you’d face a double force in the next battle, or that whomever’s potential king was captured during the Battle of Northampton would have to offer tribute or risk defeat. This wouldn’t be an open-world game with an active external map like in the Total War games, but it would be more advanced than the missions/story-on-rails from the other AoE games.
Same could be applied when it comes to a single game/battle, be it vs AI or multiplayer. Imagine a diplomacy game in AoE2 where you can plot, backstab allies, offer tributes or kill a king, but this time you’d have way more options to influence the outcome and play for the victory. You could maybe take into captivity one of the other players’ royalties and ask for resources or military support in return otherwise they’d be defeated from the game. You could maybe play a diplomacy game with external forces and receive external support in mid or end game. You could deploy traps and scorch earth on the map in anticipation of an attack.
Multiplayer wise you could have a separate mode where you would join alliances with some other players. Say you were part of the House Lancaster, and each multiplayer game you won against the rival faction would help secure territory over Britain’s map, or you could betray and capture the Earl or Duke of an ally and offer it to the enemies in return for a favour. Lots of plot and treason would come out of this one as well.
So, what are your thoughts about this? Any other ideas or different opinions? How would different technologies or religion come into play?