Can you show any detailed measurements of any speakers that can work well for this? Preferably showing pattern across angle and frequency. Most of what you say is really quite vague.
I do not believe such a speaker exist.
The pattern must be much more narrow, and fall off much faster when reaching the cut-off angles.
If you do the experiment, you realize the level must be down around 8dB at 30 degrees, if the speakers are toed in on the center position. While maintaining a reasonably flat frequency response. If speakers are toed in a lot more, it will work better, but this will have other issues, it does not work well.
What does work well, is a speaker with pattern that covers the whole listening area with flat frequency response, with a moderate reduction in level going off-axis inside this area, and falls off quite sharp outside, speakers more moderately toed in towards center. A horn can be designed to create such a pattern.
This gives a spatial presentation that is not compromised in the enter position, and good tonal balance with reasonable spatial properties outside. Images will move going off center, but that is not a big problem. For movies, where a centered dialog is more important, there is already a solution - the center speaker.