As long as it's the same universe the game can be called Syndicate. I mean, if someone would make a Mount&Blade that plays like Total War in battles and campaign map, I wouldn't start raging in the forums that it's called "Mount&Blade". Perspective doesn't matter, gameplay doesn't matter, it's the setting of the game that defines the name(and if your arguments rhyme they're convincing all the time). In general I'm against sequels that are called the same as the originals, though. For example if every Total War game would just be called "Total War" I'd be mad. There should be a way to differentiate them based on the name. You could call this game "Syndicate: A New Hope" for all I care
I have a feeling I've made the same argument regarding Fallout back in 2008 or whatever. Relax people, if it's shit, don't buy it. If it's good, don't let the genre combined with the name deter you.