I'm not so sure of it's success now, it's only got 27,000 pre-orders right now in the US. Less than knack!

Doesn't sound like it is that well known, despite people on the interwebs going gaga over it.  It is also a new IP, despite the dev team being known.  And it isn't a Microsoft pubished game either, so I am not sure it gets a Gears of War treatment.  I believe Titanfall could benefit from being bundled with the ONE though.

Possibly, although it could do better in the run up to launch in 2014. I guess if this game does well it will be due to word of mouth

A multiplayer only game lives or dies on the community new players find when they try to play.  It is a reason why, outside of MMOs, that multiplayer only games generally don't do well.  A multiplayer only game, when launching, won't have a large player base so new players don't find it.  Free to play games, with a LOT of reaching out to build community and getting people to bring their friends along, can get it to work.  This will require awhile to build up.  After this, it will tip.  The game is also going to need pockets of friends to drag their friends in to play.

We already know it's not based on preorder numbers.