In my opinion, Titanfall 2's story is great. It has a compelling narrative, excellent world-building, and it keeps you on the edge of your seat throughout.
It depends on your playing style. On average, you can expect to finish the Titanfall 2 story in about 7 hours. But if you take your time exploring and soaking in the details, it could be longer.
It's a bit of a hybrid. The 'titanfall visual novel' will surely have a storybook - like quality with its narrative focus. However, it's also a game because it will likely engage the player in ways that traditional storybooks don't. It could have mini - games or challenges within the story that are related to the Titanfall gameplay, such as piloting a titan in a specific mission within the story, which makes it more than just a simple storybook.
A crossover could involve the characters swapping abilities. Imagine Tracer from Overwatch having the ability to call in a Titan like in Titanfall 2. Or a Titanfall 2 pilot having the ability to use some of the support abilities of the Overwatch heroes, like Mercy's healing. This would create really interesting and unique combinations in combat scenarios.
Definitely. The story of Titanfall 2 is really good. It follows the journey of the protagonist and his Titan. There are some cool twists and turns, plus the relationship between the pilot and the Titan is well - developed, which adds depth to the overall narrative.