This is kinda a whatever floats your boat category in my mind. There is always room to have characters who don't need to be so deep in their back story or thought process while having actions and game play be the vassal for their character. This won't win over every person who plays it and on the surface they may not get or like the character without the added motivations to back said character up.
For me i don't care for any of the characters in gears and they all seem unlikeable in that bro dude shooter kind of way. I don't see any raw emotions that seem believable or relate-able. They don't seem all that thought provoking in any kind of way, even in the one liners kind of way. That's just my biased opinion because gears never clicked with me as I'm sure some mindless action star i like won't click for someone else.