>>345629931. More dynamic stats, serving better as a suicide lead or anything of the sort. Also, Greninja isn't a water/psychic type.
2. Tapu Fini's are legendaries, so yes, they're usually going to be more powerful than other pokemon. By that logic, any pokemon that are not Tapu's are shit. Also, Fini isn't a psychic type.
3. Same goes for UB's. Tell me what UB is water/psychic.
Just because some pokemon have more dynamic stats doesn't mean that Starmie got powercreep. Starmie serves as an excellent hazard spinner with recover and great movepool. You're just using Starmie wrong.