The reason game mechanics have stayed the same is because there's literally no reason to change them. What changes the gameplay is not the mechanics, but the evolution of the game's meta. The meta of the game evolves as people realize what moves are good, and what moves then counter said good moves, which then shifts the meta away from what's before. This has happened for as long as Toribash has been around.
I've been around to see it change. Wushu used to be a mod where jump kicks were the meta. After the kick, the game was pretty much over, as nobody was good at travelling, and people would run and tripod all the time. Suddenly, somebody discovered the sweep kick, which was a great counter to the jump kick because it avoided the kick and punished the player for it. Sweep kicks became the new meta. Eventually, sweep kicks were countered by the heli kicks discovered by KamiKo. And now we have the current meta where basically all of these moves are viable, because people have learned how to travel. Gameplay has changed dramatically for wushu over the decade without needing to change the game's mechanics. And the same can be said for all game modes.
And something being around for a long time is not a reason to change it. Geometry has been around since Ancient Greece. That doesn't mean we should change it, because geometry still works and is relevant. Likewise with Toribash game mechanics.
And if earning prestige and recognition isn't reason to play on your own account, then tough luck. Not every game will reward you with flashing lights and a pat on the back for every little step you make in a game. It's often superficial, and condescends to the game's audience.
And it would be a script to make "perks" a reality, not a mod. But, last I checked, server-side scripts haven't been done.