I don't think it's boring enough for an audience that it'll flat out receive an F cinemascore. There's too many wild shenanigans going on with gag after gag that it should be a hoot for many. A lot of the issues I agree with the critics on are mostly things a regular movie-going audience won't immediately think about (except the length and that the second half looses steam).
There's a pretty bizarre lack of action in this for like a solid 100 minutes. There isn't a big event at the midpoint that changes the status quo or our understanding of the situation, it's very strange.
If it can hold on to the 73/100 on MetaCritic (we can expect another 20 reviews, so it will be a tall ask), then that's very good for a regular blockbuster. Whether or not James Cameron and Avatar should be aiming for "regular blockbuster" territory is another question.