The ra zombie is awesome, it has saved my life, so many times. It is morely aimed toward stoping the plants from using over powered cards rather than to cripple them. Plus in the actual game of PvZ 2, it doesn't take any effort to keep your suns from being stolen. The only time it might happen is in endless mode, when there are 5 gargantuars on the screen and there is one ra zombie, in the back of the lawn, snipeing at your sun while your defending for you life. So ya, 2 sun is responsible.
Oh and for the firework zombie, Kabloom plants would totally be destroyed by it. They heavily rely on their mushrooms to get past the first levels. The buffshroom is the only defense from this overpowered zombie.
i don't appreciate that you not happy what the PvZ team spent so much time into.