Currently there is some developers working on a project that allows the hosting of Tribes Ascend servers. The project started as an alternative to allow Tribes Ascend players to play on servers where cheaters could actually get kicked/banned, as there are workarounds in the official servers to make it impossible for these players to get banned.
Now there is work being done for custom weapon settings, including damage, impulse, explosion radius, all those goodies.
Possible future work can be done for changing the physics.
I haven't had enough time to look into it all so I don't know how functional the modifications currently are but mcoot has released some videos of some of the stuff he's been messing with.
There currently is a website for TAMods, the site also contains information on custom server settings and all that.
Finally, the Tribes Ascend discord link: https://discord.gg/CF3nQfQ