In one of the many interviews with Junichi Masuda before Pokemon Platinum's American release, he stated that the Pokemon game directors were trying to find subtle ways of showing players some of the hidden Pokemon mechanics within the games themselves, specifically referencing IVs and EVs. By default, it is difficult to learn their exact numbers without the use of an Action Replay, and many casual players do not even know that such mechanics exist.
In looking at the stat screens for Dialga, Palkia, and Giratina posted on the HeartGold and SoulSilver website, it appears that each stat is by default white, but that two are always either blue or red. Seeing as most Pokemon natures hinder or increase a certain stat (such as Modest, which lowers a Pokemon's Attack stat in battle and increases its Special Attack), one could conclude that the color-differences denote how a nature is affecting Dialga, Palkia, and Giratina's different stats. Most competitive players know how natures affect stats, but this is still a step in the direction of showing hidden Pokemon mechanics casual players may not know about.
If you look closely at the screenshots below, Dialga's stats are all white except for Attack, which is blue, and its Special Defense, which is red. Palkia's blue stat is its Defense, while its red stat is Special Defense. Giratina's blue stat is Speed and its red stat is Special Defense. Perhaps red is the hindered stat while the increased stat is blue (or vice-versa).
If this turns out to be true (this whole article's assumptions could be wrong!), what other changes could we see in HeartGold and SoulSilver that could help players learn about hidden mechanics and competitive players find out the values of such mechanics? Maybe there will be a way for the games to show a Pokemon's IVs and EVs as well. Thanks go to Yaminokame for pointing the color differences out!
