This just in, video games don't always do realistic depictions of history. Unless Nobunaga really was a cat.
Developers aren't looking to make a game that won't get greenest and recognized that something action related is going to get some traction, whereas a game where you play as a figurehead not doing anything wouldn't leave the drawing room.
"Long Running"? What a clickbait title- 17 months isn't even 10% of the game's age. Maybe if they weren't doing colored artifacts for a set (pretty sure all since Shards of Alara have had them), no 2+ color lands, etc the "long running" would have been warranted.