>>55427064Sometimes it's fine to have a filler mon to pick up some slack where you want your last mon to go.
I did a Hoenn playthrough recently where I wanted to use Altaria and Sharpedo, but you don't get Altaria until the fourth gym and Sharpedo until after the fifth and there's still a lot of spots where a flying and water type would be useful - so I just used a Swellow and an Azumarill until I got them.
Think of it like the job system in Final Fantasy - yeah you invested a bunch of points into Knight already, but the only reason you were using it was because Spell Fencer wasn't available yet and you still needed something that could deal physical damage, so don't feel too bad about ditching Knight for a newer job.