I think the reason people don't fully take to Bob is because of his confessed history. It's pretty forthright of him to share that with these new people. That would be highly unlikely of someone in his situation. Your history before Zombieland might not matter all too much anymore, but your history in the aftermath kind of does, if you're to be travelling with people and counting upon them
That's the thing. The audience knows about many of the other characters' aftermath history. We know what Michonne & Tara had been doing, & we watched Daryl, Rick & Carol go through the things that got them here
But we don't know anything about how Bob managed these past 2 years, except that everyone he ever travelled with is dead. It's tough to put stock in a guy who had that happen, when you don't know how it relates to him, what culpability he has in it, if any, or if he had to make hard choices like we're seeing people make among our older characters
Let's face it, we've all debated, at one time or another, the conduct of characters who've been there from the beginning, & in this guy's case, we got nothing to go on to measure his character
So are people expecting him to get drunk and kill everyone or The Shining's All work and no (boose) makes (Bob) a dull boy?