>the original choice was Flamethrower early or better stats later, but as of gen 9, you don't need move reminders or heart scales to relearn a move
>you have no reason to not immediately evolve Growlithe to get Extreme Speed and then teach Arcanine its level 1 moves which includes Flare Blitz and Play Rough
>now you are actively incentivized to evolve Growlithe as soon as you possibly can because Arcanine will get all of its best moves faster that way
I feel like this all could've been avoided if Growlithe's evolution method was just changed to level up while Vulpix could still use the Fire Stone, which would maintain a functional difference between both fire types without invalidating either of them.
That or, if you don't want to change how certain Pokémon evolve (stupid because they've done it with others already) you could've just put a little more thought into how changing how you relearn moves would affect balance regarding most Pokémon that use evolution stones, maybe have a lategame NPC do it for you free of charge instead of charging you.