"Making the Pokémon move" would mean writing an AI for them that keeps them active enough to look alive but keep them inside the Ranch Block's (variable) limits - preferably without causing effects like invisible walls or rubberbanding. That would require more work than it may at first appear.
Additionally, features that affect a larger part of the game (improved/new gameplay mechanics, version ports, tuning of core aspects) usually have a higher priority than what is in essence a purely cosmetic feature for a single game mechanic. It would be nice to have, but short of one of the devs being especially passionate about implementing something like that, I don't see it happening too soon.
Jokes aside, I don't see how you can really make their animations more life-ful without implying some stuff