Did Nicholson consult with Caesar Romero?

It think the reason they didn't consult him was made clear in your post. Because he "phoned it in.

I think Amerigen has a point.
The Joker shouldn't at like a crazy lawyer on a motorcycle trip or a crazy Dad trying to hack up his family.

Jake Gittes was a great roll for Jack. The Joker was not.

On the other hand. I love Burton's movies. Big Fish was my favorite so far.