Yeah, weve added a few coupon slots to the book and thought about adding pages, but we think the limitation is also somewhat important too. I think we will most likely just reduce some of the sizes on a few.
there kind of is an endless mode now actually! There should be an "infinity" coupon that appears in the shop once you reach the second to last round. It can get kind of boring though since the difficulty doesnt scale enough (on top of broken combos. Haha)