I am another who is holding off playing until a solution is implemented.
The issue with co-op dialogue is that the co-op player doesn't get to see what options the other player has. This means that if they want to be involved in the dialogue, they have to wait while the other player reads the options/decides what to say.
Improvement such that both players can participate/see all options in dialogue is required. I also agree with sentiments that the alternatives are generally immersion breaking.