I've seen this topic pop up in various servers I'm in, but one thing that really bothers me is how much dialogue is locked behind tadpole usage. Especially after you have the dreams, and you can speak to each of the companions in turn and get some pretty unique dialogue (often about their backstories.) I was avoiding using the tadpoles until I realized how many interesting convos happened after each of the dream sequences.
Don't get me wrong, I have no issue with some conversations and scenes being specific to certain choices (such as the dreams themselves), but it would be great if there were other dialogue options for players who choose *not* to use the tadpole, as they shouldn't feel like they're missing out.
I am pretty sure that all those companion conversations, also offered either a regular wisdom roll or a persuasion roll. You had the illithid available if you wanted to guarantee that you would win the roll, but there is always other methods in regards to the companions. So your not really railroaded into using it, unless you really want to to open convos with them.
Convos with other NPCs is a different story, sometimes you just have the choice of using the tadpole.