In terms of server performance ARCCW would make our stuff way laggier and weapons would perform worse.
It's a great modular system for smaller servers, but it's not setup well enough to work in 100+ player environments.
TFA may be older and more simplistic, but newer versions provide some of the same things ARCCW has in a less intense way. Though you sacrifice some flash for that performance gain, such as animations fancy UIs for swapping etc.
I do admit, ARCCW is super cool, but it's not practical here