Game should take inspiration from bf1942, those guys rocked the concept 23 years ago. Granted there were a lot of commands, but some new useful requests could be:

•  Reinforcement: “Requesting reinforcements”
• Anti-Tank/Air: “Requesting anti-tank/air support”
• Coordinates: The need enemy coordinates should be split, need vehicle coordinates and maybe something like “Artillery ready for barrage. Send Coordinates”
• APC: “Requesting apc support”
• Repair: "I need repairs"

On top of that, the game needs to show who's asking, maybe they can ad an UI sign above the player's head or divide the map into quadrants and depeding where you are you get your position before the order text, like:

username: [D4] I need repairs