Mine are more about the condition as well as design:
BOP (and others): ramps not designed to withstand the abuse they take given their location, standing targets too random to activate
Bad Cats: Again, ramps - fishbowl ramp to extra ball can be too easy, don't like that jackpot can be activated by the seafood wheel, takes away skill from a high point score
Doctor Who: Standing targets a too random, perhaps I just need to practice on skill, art is lacking - bg gives doctors weird expressions, would've liked more specific objectives to match each doctor