Everything has two sides and the “all chat” is no exception. It can help you punish griefers. You can coordinate with the enemy team if someone on your team is not playing properly and willfully trying to be malicious. Although someone on your team might be toxic, the enemy team might still be good sports and work with you. Sometimes the enemy can use all chat to give you information about griefers on their own team or even bots.
The All Chat in World Of Tanks can take away from the immersion however. Communication with the enemy and real life warfare is not as simple as pressing your keyboard. It can be used for misinformation. It can also be used for trash talking. Griefers on your own team can give away secrets to the enemy team. However the enemy team cannot always trust this information, because in the spirit of counterintelligence you can give away false information to mislead the enemy team.
On one hand the whole chat is an opportunity for you to banter with the opponents. On the other hand it can be used as a tool for increasing toxicity. Even though the all chat is gone now, there’s still the possibility of a lot of toxicity within your own team.
One of the main problems of all chat is when your teammates die and they tell the enemy where your position is. One solution to fix this could be using chat the way it was done in CounterStrike. If a player has died then only other people who have also died will be able to read their messages. People who are still playing and alive can only hear the chat of people who are still playing and alive.