Astro in savage

[Lastelli]

snip

I confess I got a little lost in your argument with RichardButte. However, I feel like a 1.6% dps increase at the very least is a decent enough compensation for the current weaknesses of AST. Remember that using AST basically means that your co-healer cannot dps optimally (and you cannot dps as well because mana issues and weak healing) and this is a huge problem. The numbers you showed would still not be enough to replace a SCH's missing dps. Double AST isn't possible because you would lack healing power, the party would just die.
Also

Expand Balance / Arrow = 10-15% increase in raid DPS 55% of the time = 5.6% to 8.3% increase to total raid DPS

should be divided by 2 (the effectiveness of cards is halved when expanding). It would still trivialize very short (30 seconds or less) dps checks, yes, but in the long run it should be ok.
I believe that a more interesting case to analyze is the current contribution of AST to the raid dps. Again, assuming you will RR the first card and use shuffle on the 2nd draw, the probability of having an expanded arrow/balance should be 1/3*(1/3+1/3)=22.2% (actually a little higher because of spread, but let's keep things easy). The probability of having extended/enhanced arrow/balance are the same. Assuming balance=arrow for dps increase (I'm not very comfortable with this assumption, but still...), this basically means that this will provide an expected raid dps increase of 22.2%*5%/3+22.2%*15%/(6*2)+22.2%*10%/(6*2)=0.37%+0.28%+0.19%=0.85%.
I assumed that CO is used on the expanded version, time dilation on the enhanced version and some other assumptions about the contribution of the "best" dps player. Also I'm assuming constant dps (no "burn phases"). Let's multiply this by 4 (i.e. let's assume arrow/balance are 40%). We get 3.4% expected (avg) dps increase (similar to what you did). This is just to say that the idea of doubling or even tripling the effectiveness of cards is still not enough. Even more, an avg 5% dps increase (that is what you computed as the avg for a 60% arrow/balance and I think you're very close) is hardly better than a SCH that can full dps (mind you, the SCH is doing 5% of the raid dps in the parse you posted, and SCH+WHM is 7%) because it's an expected (uncertain) value, which is always "worse" than the same certain value unless the party really loves risk. Let me make this extreme example: 60% balance, expanded (30% raid dps increase) for 20 seconds every minute (CO on 60secs cooldown) and you draw perfect cards=10% total raid dps increase in the best case scenario. If healers can't dps because healing is harder with AST, this isn't much better than having WHM/SCH and healers can dps: according to this parse, it means 8130 raid dps with AST's buffs versus 8020 raid dps with SCH/WHM. Doesn't look too OP, right? As Zholi put it

Their (cards') power needs to be boosted so much that most people's initial reaction will be that the developers have gone overboard.

So...yeah I can't see an easy solution. Statistically speaking, a 50% effect of cards should be about right to make it on par with SCH/WHM if (big if) we believe that healers cannot dps when there's an AST in the party. However, this would make all short dps checks really easy to handle. But there's more: in a very lucky try (AST drawing very good cards) a party could meet dps checks too soon and the more hardcore parties might be able to clear the content in a few days, depending on their luck. This is why I think AST should be revamped. As you said, if they simply perform some fine tuning on the current skills I believe (hopefully I'm wrong) that AST will never be a viabe healer for raid progression...a pity. On the other hand, if they make AST statistically on par with the other healers, there will always be a chance that a lucky party will clear the content too soon, making AST mandatory for raiders aiming to world and server first clears.
Right now however cards are not enough even to compensate for AST's weaker dps.