The biggest general change in MotM is the fact that ALL races can either:
- Add their attribute bonuses to whatever abilities they like, thus freeing up races from being niche picks to match classes.
- Allowing either a +2 and +1 OR a +1 to three abilities.
They did make specific changes other than that but that was the major shift introduced.
Edit: The other primary change is that racial at-use abilities that were usable once per long-rest have, for the most part, been altered to be usable a number of times equal to your Proficiency Modifier per long rest instead.
😉