Many legitimate uses of 3rd person. The servers are also far more popular than 1st person ones. What they’re doing is acknowledging the problem, acknowledging that server-demand will drive in favor of third-person allowed servers, and proposing a compromise that perhaps eliminates the worst of the offending, at the very least taking the edges off it.

Removal of a feature should not be taken lightly, and Dean Hall isn’t convinced they should remove 3rd person at the game level (source). Anyways, they want to remove remove the crosshair but it may will have it configurable by servers. Same with 3rd person, but no firm decision is made yet. They need to test everything out. Hacking is something they will have to work on for the life of the product. I.e. forever. Dean Hall has to try this new architecture and continually innovate, adapt to the change of pace (source).

Possible Fix: Arma 3 mod 3rd person camera fix

Press [Enter] on the numpad in-game to view the third person camera

It has been demonstrated that there is a “problem” with the allowance of third person, and the proposed solution is the best they can come up with. It’s not perfect, but if they just allow servers to turn it on/off then, demand will dictate that people gravitate to ‘third person allowed” servers – despite them acknowledging the exploits (source).