Don't spam /say for unimportant stuff like tranqing; It blocks space you need on bosses for important things like trapwarnings (LK) via /say chatbubble.
type /ec in game to bring up Elv Ui config. The first screen you see will be the general section. Towards the top in the middle there is a dropdown menu where you can pick where the message is displayed.
Honestly, I just think it's incredibly annoying with people shouting all over the chat when they use an ability, bar from the tanks and possibly healers.