As you mentioned in the TH, this won't be a problem for card stackers, as they can afford to have dead cards until season end, however I think that for those who don't, having dead cards in their deck for ranked battles and brawls will be too much of a disadvantage, making rentals very attractive. This in itself would be good for people renting their cards out as it is sure to spike the rental market, especially as fewer and fewer cards not on cooldown are available. Ultimately though, the intended demographic for this playing mode wont need rentals, but I think that for at least the first few months many people who really shouldn't be playing in this mode will do simply out of curiosity. I for one don't feel that this mode is for me, as I'm not a card stacker (for my play I'm just happy to have a single maxed deck to play with), but I feel putting the spares that I do have onto the market could be a good play initially. Having said all that though there's bound to be other factors that we haven't considered yet coming to the fore, so like you said, exciting 🤠