I think the new Bruce Banner actor is great in the role. Before they always tried to make him this skinny, nerdy little guy and you don't have to. Bruce Banner is just as compelling a character as the Hulk is.
I think the Eric Bana portrayal of Banner was actually pretty good. I think you could see that inside of that guy the Hulk was always there under the surface. He was someone with rage and personality issues. I think the Edward Norton Banner suffers the problem you mention, that Banner is kind of milquetoast. I could see why they went that way, but it turned the Banner/Hulk dichotomy into too much of a duality: two different people in (sort of) one body. I really like the Mark Ruffalo version of Banner in that I see a little something of what I saw at times during Peter David's run on the Hulk where the Hulk wasn't just a monster that Banner turned into but was an aspect of Banner himself. Although it was described as a multiple personality, it was actually characterized more as a splintered personality with the Hulk and Banner different aspects of the same person. Ruffalo's Banner is interesting to me because he isn't "the other guy" to the Hulk's "other guy." Whether he wants to admit it or not he is the Hulk.
Along those lines one thing I didn't like about Leto's Joker compared to Ledger's Joker is that in Suicide Squad the Joker is portrayed as actually
running an organization. The Suicide Squad movie is certainly not the first time the Joker has been portrayed as such, but to me the way it is portrayed undercut the manic unrestrained aspect of the Joker that Leto seemed to be trying to convey. His Joker is a new age emo Joker that spends time scribbling on walls *and* runs a criminal organization? The Leto Joker seems to be at least two different people, and not in an interesting multiple sides of personality way. More like a pair of twins pretending to be one person and living separate lives.
The Ledger Joker is comprehensible even in his incomprehensibility. We can at least conceptualize that Joker even if we can't actually relate. We can at least conceptualize the Nicholson Joker even if we cannot relate. I cannot really conceptualize the Leto Joker, and there's no such thing as the artistic decision to portray a character that can't be characterized by the audience (or if there is, its generally not a good decision).
When I look at the Bana Banner, I see the Hulk as something inside of him. When I look at the Norton Banner, I see the Hulk as something he becomes. When I look at the Ruffalo Banner, I see the Hulk as something he
unleashes.
When I look at the Leto Joker, I don't know what I see (figuratively, not literally: I have eyes). And while there are those that like his version of the Joker, I still think that's a problem.