I think you are reading too much into their expressions. They look like they have a lot of fun when they win, and if they look like they are loose when they lose, well the fans don't like that at all because why should they be loose and happy when we can't be. Scioscia tries to keep things on an even keel because he knows the season is so long. It's detrimental to get too high or too low because you can't sustain the former, and you don't want to sustain the latter. If you want to see what can go wrong when you replace someone like Scioscia with a fiery type you don't have to look any further than the Francona to Valentine transition last year - disastrous.
If Scioscia is replaced Arte better have someone real experienced and well qualified to replace him with before he pulls the trigger. Fans are very reactionary, they don't think things can get worse. They sometimes think that anything is better than what is happening currently. The truth is that the wrong move here could set off a chain reaction of mistakes. DiPoto would push real hard for someone loyal to him and who agrees with his philosophies. I'm not sure I trust DiPoto enough to let him take greater control. His performance is every bit as suspect as Scioscia's right now.
I hope that Arte has someone outside the organization who he can turn to for some advice on this one, someone impartial who is extremely experienced in baseball operations. Like a former GM or owner who has navigated this minefield before. He has to shut down on listening too much to his GM, manager, fans, and press/analysts and really think about what can be done to achieve the objectives he wants.