He's a little like Jesse Eisenberg.
Nah bro...
Yepp. RDJ is not a great actor. He's just a very charismatic dude who sometimes wears makeup. He's a movie star. His range is how loud he raises his voice.
He's kind of like George Clooney in a way. He's not a bad actor, but they use a charm to get them through their performances.
Most actors do unless they are character actors.
It depends. Al Pacino can act the same, but he's able to change his voice like in Dog Day Afternoon.