Well for the first part, about Chara tee development, I do that same thing all the time. I love thinking exactly how my character will function and what he'll look like at the end and how I get there. Now I don't think random dice affect this planning, but I'm not exactly sure how you think it does? I'm not trying to be cynical, I'm just not fully understanding what you mean.
I think the dice can have an impact on tactics however. I have to agree that parties of four tend to create more jack of all trade characters, but I think it's still somewhat possible. I think we'll have to wait and see how dedicated roles can be when ea comes out, cause I'm not sure.