I think it may depend on what day you go. First weekend the mall is major busy and hard to get into. Lines to get in then more lines to see the characters. I would think after the first weekends merchandise crew is done it may be easier.
I do think the one advantage of the characters in the mall, is they are not visible so the people that just walk by and say "oh look mickey in a jedi outfit" and jump in line are a lot less.