@PurpleKudzu423, you came to the party late. He modified the post after I called him out.
Not only that he just added a few more plants that he thought were overpowered a even fewer that he thought we underpowered. I mean look at the detail he goes into with the zombies. Remember he had like 3 or 4 plants when he made the post. Then I call him out and he half-heartedly adds a few plants. I honestly think the original poster only plays zombies or plays zombies most of the time and laments the time he is stuck on team plant.
The game balance isn't perfect but I feel its in a great place.
Turf Takeover - doesn't really matter what team you are, if you are defending the odds are heavily in your favor. The only exception to this is moon base Z which is the most balanced of all TT maps. Zombies stand no chance on seeds of time and plants stand no chance on zomburbia. (by no chance" I mean slim chance)
Suburbination - Zombies win slightly more than plants when I play, I would say the zombies more aggressive skill set helps out a lot in this mode (especially imp punt)
Gnome Bomb - I would say plants win more than zombies in the mode and I'm not sure why. May come down to abilities and being able to setup a good bit of defenses that are set and forget. (they can leave the gnome with spud mines, tall nuts, chilli bean bombs, etc in place and leave area to explode).