It’s been considered, but I’m not sure if anyone has tried yet.
The biggest problem is that the IMU refreshes way too slowly, and/or that we don’t know when the IMU updates.
Therefore, with an IMU that only updates around half as fast as the encoders, it means that the arc approximation will be inaccurate if you update the encoders faster than the IMU, and if you slow down the loop you end up with worse odometry.