I don't know if bobby was ever stupid, in the early season's he was always very quiet and deferential to his superiors (tony, junior). He actually seemed pretty savvy in how he acted in the life having grown up in it with his dad.

I think bobby would have been a smarter boss than he let on, but I don't think he would have ever been fierce enough to command the respect of the heavy hitters. Bobby had a sensitive side and we saw how those guys reacted to johnny sac crying at his daughter's wedding. I don't think guys like paulie would have listened to bobby