I got an idea, assuming it hasn't been implimented or suggested.
Suggestion: Proper EV training method
Description: Due to fire red and leaf green lacking the EV reducing berries seen in emerald the only way to effectively EV train up till that point was to breed all your pokemon once you were able to reach the breeding center, which I always found to be a huge ripoff because some of the pokemon you would meet along the way that you use in your first e4 run might have already had good IVs and possibly a good hiddenpower attack in turn. Trying to breed it over to EV train it would have likely screwed everything up (especially since destiny knot/power items didnt exist to retain IVs during breeding). To make up for this I was thinking of possibly a variant of X/Y's super training to increase/decrease EVs using the mini games seen on 2 Island as a base.
Relevant Area: Possibly scripting
Related Research/Method: Hex editing (maybe? not sure but its the best I can think of)