I like the Artifact Assault team-based mode very much, yet I do think it can do with a lot of changes. Right now, many players use the teleport and smokebomb ability to quickly get the enemy's artifact and to get to their own base. That's not so very nice, because I think the game would be much better if the players really have to get to the artifact in a stealthy way and then make their way to their own base without using such things as teleport.
I don't like the hidden gun either, because now players can quickly kill their opponents and reclaim the artifact. I hope the AC team will do something about these game modes and make some changes.
Although I don't like the smoke bomb, hidden gun and teleport, the artifact assault game itself is very nice. I always get a thrill when I've taken the artifact and I love the fun once I've made it to my own base!