I’ve actually never played Arkham Knight, I’ve just heard the complaints so I can’t comment personally. I haven’t played any of the batman games.
I think games were better back then in terms of game design. I think another big part is that developers were more-willing to take big risks. Often a dev team would only be 10 people or less, there wasn’t a huge amount at stake. The genres we have today were still being formed and developers were constantly trying new ideas, pushing the envelope and making unique masterpieces.
Today the dev teams are too big: often hundreds in the core team, plus addition hundreds (or a thousand) outsourced for models, textures, sound, etc. There’s too much at stake, so the developers can’t afford to take risks and break new ground. Instead they just follow the cookie cutter formula. Most of the focus is on graphics and often story and gameplay are ignored.
There are so many incredible games from that time and they are still incredible, and it’s not just nostalgia. I can think of hundreds of examples. Thief is a good one, look at Thief (1998), a brilliant game and it still holds up today, still (after nearly 20 years) the best stealth game ever created. Compare that to Thief (2014) a horrible abomination of a broken game, even though the team was larger, it was more expensive to create and it probably make more profit than Thief (1998). The horror.
It’s difficult to describe why modern AAA games are awful because the reasons vary. Sometimes it’s like an interactive movie, too many QTEs, broken console ports, games without story, games without any originality, games without gameplay. Games that stick to a tired old formula. But admittedly there are some exceptions, there are some great AAA games. Things are improving now though, ever since the indie explosion I think AAA devs have realised they will have to start being creative because people are sick of seeing the same tired old manure heaps each year and they’re looking to indie devs instead.Plus with kickstarter now publishers have less power, visionary devs are able to leverage more creative control.