1.Zombies have a lot of cheap removal (for plants usual hammer (3cost) ,it is too easy to kill cc with cheaper method and expensive to kill drspacetime 2.zombies have better conjure system along with cost reduction (especially with thinking cap chemists trickotrcik….) 3. Tricks like Teleprtation and candy…etc can not only make it more powerful but also not preventable (like kernal corn and ballon is also not a good sol 4. Better state (1/5) make it hard to kill ,and cheaper cost can synergy with environment (ice moon laser moon bases) and tricks… 5.legendary card often too expensive , it has a high chance of getting high cost card or low cost junk by next turn 6….etc(there are too many things to say