I dont know much about game development but I know that in general just adding more people to work on something doesnt always fix an issue.
That's true, but considering how many projects Game Freak has been working on at the same time, there is no reason not to slowly add more people to those extra products to train them well before the big title starts its development. Or they could just do like Nintendo EAD and Sora LTD did with BotW and Smash and just ask another studio for help. Nintendo would surely give them all the manpower and resources they could spare, Pokemon is a vital part of their business.
You know it deserves the GOTY.