I don't think they're overly big, I think they're perfect for capturing a relaxed look.
The BR lips and squinty eyes make him look very focused, like the "you remind me of my father" moment.
The new eyes and lips are a nice, neutral, but not lifeless, representation of him as he sits at the mob meeting or pacing around the Prewitt building.
Like Jack Sparrow, Joker's tough to capture in 1 head. Really, there's probably at least 10 variations you could come up with between makeup and expression.
Of the 3 heads (BR, BR masked, Mob), I'm glad the Mob has a look that represents the average look Ledger had in the film. If we can't get every look, I prefer one that best represents the character. Of the 3 heads we got, I don't think HT ever really captured Sparrow that way, the smiling head was too smiling, the cannibal too specific, and the first head too serious.
The big smirk on the masked BR head ruined that portrait's versatility for me, the posed eyes and particular expression on the BR are pretty limiting. Between posable eyes, the makeup and the expression on this mob head, I think I'll get the most versatility out of it that I could get out of any Ledger Joker head, which is great.
Now, my perspective is as a photographer and I use my figures more than others. I can understand how folks who just display their figures have specific poses/dios/etc. in mind and would be bummed not getting a portrait that lends itself to their ideas.