It’s all relative… bigger turbine making the same HP you don’t need as big a wastegate, but with generally, a smaller turbo just won’t move as much air, the engine wont make as much power and there will be less exhaust gas so you don’t need nearly as large a waste gate. This effect is probably greater then the turbine size changes, especially since you can have turbine sides that are the same physical size, flow the same but have a different AR….