Having the game start with a default chat color set would be awesome for mobile gaming. It is really difficult to touch the color settings on some resolutions and would generally be a nice QoL improvement for new players and veterans starting the game on new devices for the first time.
The default set would just auto-activate if it cannot load or find a saved custom config entry.
The following example shows how the default chat colors could be colorized. (Inspired by common colors in other MMOs.)
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(System Message) System: You have used Max Repel!
(Help) NewbLife: Hey, where can I find Ralts?
(Battle) Legend_27: GGWP! You are a strong trainer!
(Battle) TheRealRed: WP. Nice battle and thanks!
(Help) Trainer42: You can get Ralts in Hoenn - Route 102.
though it is pretty rare.
(Trade) Traveling_Trader: WTS perfect Bidoof | max offer or
900k instantly
(Local) Dude: Hey.
(Trade) Messy: WTB all the Pidgeys! 10k/ea
(All) Cthulu: What a great day it is to slaugther the Johto E4!
(Guild) Mate007: Hey comrades! How are you doing? :)
System: Repel effect has worn off.
(Guild) Yaboi: Hey there! All good here mate! :)
(Local) Dude: You look really cool.
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Additionally, if the system messages stays green it should be changeable, because there are 6 default text channels and 6 colors to choose from, including the same green the System Messages are colored. This means you will end up having a green text channel mixed up with the System Messages.
Lastly, one might argue with this, but by adding "(System Message)" as prefix in front of it readability would be improved through uniformity.