That's the thing. That's not what people wanted to see, as evidenced by the diminishing box office returns (which proves that it's not just the critics hating on this movie, the word of mouth from average moviegoers is bad as well).
What sells this movie is not the 2 heroes fumbling around to find themselves. It's the clash of two people who mostly want the same thing , but have different ways of going about it. Whether the movie was going to be dark or lighthearted, the clashing of those 2 people and their ideologies is what people wanted to see.