One consistent topic on Mark Rosewater's Tumblr blog has been various types of color pie grievances. These range from fans of a particular color raising complaints about a perceived lack of depth, to "why does blue get to do everything," to calls for a sixth color. The most valid of these lines of questioning, however, have to do with the lack of combat mechanics for blue beyond flying and for things for red to do outside of combat. However, recently, we seem to have gotten a concrete answer at last:
When karric asked, "Can we get a progress report on red's color pie development/blue's combat development?" Rosewater responded:
You can as those things become public. I am happy to say we’ve been making progress on each but it’s going to take some time for you all to see it.
This is encouraging news for the health of Magic as a whole, not just those two colors in particular. As the game strives to spread its focus evenly between creature combat and noncreature spellcasting, blue deserves to have more to its combat abilities than a couple of straightforward ways to not be blocked. Meanwhile, red has always been a little deficient in its color pie slice, perhaps because so many of its effects are straight-up destructive - ask any Magic player for examples of things red spells do and "burn," "land destruction," and "artifact destruction" are probably the first three answers you'll get, with "power pump," "fast mana," and "spell copying and redirection" (the last of which it shares with blue) taking a while and things like "sorcery recursion" maybe never coming up at all.