Something that later series do better than older series

I think we can all agree the newer series do much better when it comes to type effectiveness. In OS and AG, it was common for moves to hit Pokemon that they shouldn't be effected by. Pikachu's electric moves hitting Ground types is a common thing people bring up but there are others. In the Hoenn League, Ash's Glalie knocked out a Misdreavus by using Headbutt. But Misdreavus is a Ghost type and shouldn't be affected by a Normal move. Another example is in the Orange Islands where Charizard was hit by Marowak's Boomerang despite being part Flying. Since DP, the anime has made a lot more effort to portray type matchups accurately. There are still mistakes from time to time but not as much as before