I am in favor of this proposal for two reasons: (1) I <3 Matt, (2) I feel promo cards are generally beneficial for both the company and the game.
I would echo @azircon's point about wanting to get feedback from Creative & @nateaguila on this. Ultimately I think the decision on what card to create should be entirely within their control, and while the community can suggest a particular theme they should have the power to adjust it as needed. E.g. perhaps they choose to have it be "inspired by" rather than a literal adaptation.
Finally I wanted to make a comment on how to get more value/sales/engagement from future promo card events. Previously (when there were no points multipliers for early purchasers) the issue was people sniping at the leaderboard at the very end. Now the issue is that 95% of the action happens on days 1-2, and then there's virtually no engagement after that.
My suggestion is to have the prizes evenly distributed across the days of the event, while the titles would be based on total purchases for the entire period (with or without point multipliers, but personally I'd remove the multipliers). For prizes imagine there are 1000 packs getting distributed and it's a 10-day event: instead of distributing those based on points at the end of the event, you would distribute 100 packs/day based on daily purchases. This would encourage people to consider making purchases each day in order to have chances at the prizes.
I feel like this system could help us keep away sniping while also ensuring participation throughout the event. Also whenever people get prizes that's a "marketable event", with people potentially sharing what they win with their networks. It's a similar strategy as doing drip campaigns in marketing where you want to have sustained noise over a period of time rather than putting all the fireworks at one time.