Depending on your application, listed below are the alternatives,
The BMI088 offers data synchronization features between the accelerometer and gyroscope that you will not be able to get with the BMA456+BMG250 combination, but doesn't provide smart accelerometer features like step counting, wake-up on tilt, etc.. It hence boils down to your target application. High performance where you only need well synced accelerometer and gyroscope data, or you need low power IMU data (not synced) with smart wearable features. If you would like to have both, then the BMI270 is the best option.