This is how i see Ash's current Pokemon, power-wise. I have seperated them into tiers.
1) Pikachu, Charizard, Squirtle, Bulbasaur
2) Infernape, Sceptile, Snorlax, *Torterra, Swellow, Staraptor
3) Donphan, Corphish, Buizel, Heracross, Glalie, **Gible
4) Bayleef, Cyndaquil, ***Torkoal, Kingler, Tauros, Muk, ***Noctowl
5) Totodile
*Coming Soon
**Ash's first Dragon type. Of course we need to see it in a decent battle, but I believe it'll do as well as the others in 'Tier 3'.
***So much potential. Should move up after its usage in the Sinnoh league (if thats what the opening means).