Here's where I'm hoping some smart director is able to ask, "why should his voice only be thunderous and hard all the time? My voice is different when I'm angry from when I'm calm".
Short-sighted filmmakers have not been able to make the Hulk into a real character so far because they seem to think he's one-dimensional.
Hence the problem with the Hulk character and why they should perhaps forget about it for a while until it becomes affordable to make it right. If they keep doing it wrong they could permanently damage the character in the public consciousness.
The Avengers movie could be the best thing to happen to him. Surely there cannot be enough screen time to devote to the usual Bruce Banner angst that normally dominates the story.

t: