So at current there are a handful of non-weapon rare cards. They include (but aren't limited to) Miracle, Pharaoh, and Arctic Squid/Octopus. I was thinking the other day how I wanted to get these cards simply due to them being rare, but at the same time having no need for them since I don't regularly play any of their colors. Then it occurred to me: Why don't all colors have at least one rare card (not including weapons)? In the ideal world, I think it'd be cool for at least one rare Creature and Spell for each color.
Obviously these would have to be new cards though, since it wouldn't do any good to make something common now into a rare as it would only effect new players. Still, there's plenty of good cards sitting in the Forge just waiting to be implemented...