It's not that it is a terrain card - Wall of Fire isn't green. It's not that it is uncommon -Acid Spray isn't green. It's not that is came from a green item - White Orb doesn't make green Big Zaps.
Colour bar denoted "quality" doesn't it (not to be confused with rarity)? Can't say I know where green places on the scale though. "There are two concepts associated with each card that are easy to confuse but importantly different. The first is the card’s “quality”. That is a rough estimate of the card’s power and is indicated by the color of its title bar. So, the gold Dwarven Battle Cry is more powerful than the bronze Charge which is, in turn, more powerful than the plain Blind Rage. Of course, these quality assessments are subjective, and a large part of the fun of deck building is deciding whether or not we got it right. Is Blind Rage actually a good card for your deck? Or maybe Dwarven Battle Cry isn’t that great in your Elf/Elf/Dwarf party…" From dev diary here: http://www.cardhunter.com/2012/10/card-rarities-2/
Color of title bar detonates card quality with seven ranks. Off hand I think green is rank 6 with the ranks being Black 1 poor Paper 2 weak Copper 3 average Silver 4 good Good 5 great Green 6 Purple 7 The c, u,r refers to how complex the card is. I'll admit I find this a poor decision as it comflicts with every other game out there causing much confusion.
I have no qualm with the game using a grid system for (x quality, y complexity) rather than having a "rare is always the best" cards. That always strikes me as uninspired design.
I believe that it's part of the AI decisions, but it's more than that. Card quality is supposed to be a measure of how "good" the card is, probably the best guess estimate of how valuable it would be in multiplayer. The sum of card qualities also determines an Item's quality level and/or talent cost. Woodman's Axe Level 1 Common Weapon 2x Chop (Copper)2x Weak Chop (Paper)2x Weak Strike (Black) Cleaver Level 4 Common Weapon 2x Chop (Copper)2x Weak Chop (Paper)2x Simple Strike (Paper)
Quality (title bar color) is a measure of the card's power. We use it to determine what the level and talent requirement of an item using it is. Think of it as roughly analogous to the mana cost of a card in Magic.
I don't think it's the quality bar itself which is causing the problems but the rarity indicator and to be honest I can't see that having it there adds much. From a design perspective it is needed as it relates to the item budget. In a lootcentric game having rarity is important for that psychological rush of finding an epic drop but that is already covered by the item level/rarity. Knowing the card quality is important so that when playing you have an idea of if the card is good or bad. Knowing the card rarity doesn't really seem to add much to this and creates confusion on what exactly all these item indicators represent. Dropping the C,U,R on the card (and perhaps emphasizing the quality bar a little more during the tutorials) would make card and item evaluation easier to understand without sacrificing the useful information.
I think we need to reinforce the discussion of what the quality colors mean. I'm intending to do this through load screen tips once we get that in.
