Imagine you have traveled back in time and you're on the team to create the generation I Pokemon games. Because you are from the year 2013, you know things from gen I to gen V, and you already have certain things in mind you wish had been in gen I just to make it a little less painless. You are allowed to add only one feature from any generations past gen I. What do you add? Removing a feature can also count, but remember, you can only make one change. As this is all hypothetical, you don't have to consider hardware limitations and such, unless you just want to be more realistic. If you choose to not add a future feature, why would you make that choice?