I find the Foot Soldier to be sniper enough for the zombies, personally, and then that to be balanced out well by Scientist that instantly get into "your side" of the map, and wreck all your tunnel-vision and flybot-commanding Cacti.
It's also worth noting that the Cactus defense walls don't reach head height, while the Zombie All-Star's do. Thus, it's a lot more useful to pop a Zombie barrier and revive in the middle of fire (plus the smokescreen of soldiers) as opposed to... ANYTHING the plants have.
Sunflower Sun beam is pretty much asking to get a soldier Rocket, Punt Imp, Charge, Football Gattling, or concrete shot to the face. And the fact that she has NO way to cover herself if enemies get close... probably the only class in the game without some form of "get off me" move.
I actually miss the All-star when I'm not on the Zombie side. His tackle is way to good a move to use as a simple "movement", as it takes some time to recharge. Imp Bomb is ALMOST a Chilli Bean Bomb, which I find pretty surprising from the only class that can flat out survive the bomb and retaliate.
Engineers Concrete shot is possibly the worse "person to person" gun, but I love it in G&G. Easy way to clear Potato Mines, hit the enemies, and clear out their potted plants and spikeweed. Also very fun to hit people around corners, who think they've escaped your killing blows. Drone's bomb-strike also charges pretty fast for something you can summon from large areas away, and sit around to charge.
I really love how the balance is in the details, and not directly in a class-for-class comparison. That's probably what keeps me most wanting to play, aside from earning items; I generally miss playing one teams members when I'm playing the other, and even similar characters have me calling for that one unique trait of their "clone" when playing the other.
Lost all my coins, servers are down, sticker shop is down.
That probably means you're disconnected from the server. The coins, levels, and such, are saved server side, so you'll appear to have nothing when not properly connected.