That sounds interesting ...
But i would be aware of overusing it ... after all, all our companions seems displeased (maybe except Astarion) of us when we use our tadpole powers. It might just create another nonsencial situation in the proces.
As far as we know, communicating telepathically has no negative effect on the party. Tav and the companions *do* use it from time to time, and it never triggers an illithid event. The only time an illithid event is caused, is when they use the tadpole to control someone, but not to communicate.
I agree that I like Astarion's subtle hinting as it stands but I still think there should be an option to ask him telepathically how they want to handle it, go straight for the kill, let Astarion handle it, or try to get information out of him. Wyll is usually the biggest offender imo, he constantly suggests fighting and killing people that Tav is talking to, especially in the goblin camps. Why would they let Tav wander around freely when one of their companions is always begging to be allowed to kill whoever they're talking to lol.
There's also that moment with Lae'zel when everyone meets the Githyanki patrol, there's a persuasion check to whisper to Lae'zel to play it cool... Why not just use telepathy? I really could go on and on lol.