So far, Ash has won most of his battles. It is guaranteed he is winning against Bea. He is going to need to get a few losses down the road. It seems the writers are afraid to have him lose. Now I know he lost against Bea, and 2 other trainers, but that was back in the Great Ball Class which was a long time ago. So far, he is not on the level that makes it believable that he can compete with characters such as Cynthia or Lance. Now we know what Journeys is most likely going to do, and that is nerfed them to make us think Ash is strong enough which he isn't. I hope it's not the case, but that is the only way I see him beating those 2 champions.
Now, considering Ash's team, there are 2 Pokemon that definitely need wins such as Sirfetch'd and Gengar. Farfetch'd won against Genba and Rinto later on when it evolved. Give him a few more wins. Gengar's last win was against Surge's underling's Raichu which is definitely unacceptable. He needs a couple of more wins. If we are going to expect Ash to use reserves, have him get more wins with the pokes that rarely win at all first. Then, we can focus on subbing some Pokes out.