Open Your Mind
It’s been a complaint of shooters of the past five or so years that they guide along a narrow corridor too much and don’t offer much in the way of variety. You just go one way, take down some bad guys, repeat. Another is that missions are just like going down a checklist, which isn’t much fun.
Titanfall 2 doesn’t need an open world in the style of say, Assassin’s Creed or GTA, but missions should take some ideas from them to heart. The AC games give players optional objectives during missions that can help lead to a full 100% synchronization. Ideally, Respawn would look at those and go, “let’s do that, but with giant robots”.
Optional objectives during robot warfare missions would add replayability to the campaign, whether that be sabotaging enemy Titans for the next mission or securing parts to upgrade Titans on your side. Other games, such as Infamous, have stunts that you can do; “headshot an enemy in midair”, that sort of thing. This sort of metagame would be fun in Titanfall 2. The game could ask you to wallrun onto a Titan, disable it, then gun down an AI enemy for an XP boost. There’s always a way to add some more fun to a campaign.