i think tremulous should have a knife that can be used as a secondary and when u r grabbed by a basi u can turn around and knife it and it looses grab!
That takes away the only good thing about the basi. Seems OP to me.
Basi is op for low latency users anyway, more so when the enemy has high latency due to the client-side prediction errors which basically makes the avatar warp around whenever he is grabbed/ungrabbed.
Perhaps swinging the blaster gun around using secondary fire like in xonotic might work since we wouldn’t need any new animations or models, and simple free sounds for something as common as swinging an object around can probably be found on the net legally somewhat easily. If you’ve ever been on the Z (zombie) server in 1.1, they make use of the reload/change weapon/gun drop animation to swing the axe which is pretty innovative in my opinion.
Virus HQ video as always 
Is that a trickjump map at the end of the video?
To the idea: I think basi is well balanced now.