I agree almost with everything you said and I like your layout more than the one proposed by SJG, but for one thing: sure the old plamats' double space for classes and races was better than the vertically overlapped one, but the horizontal overlap is even worse: the vertical overlaps allows to read the title of the card on the back, the horizontal is useless, it only allows to know that there is a second class/race. I'd put back the double slots making 3 columns in the bottom left quadrant, one for classes, one for races and the third for everything else (so the available space for this will be reduced, but there are not so many cards which have to go here now you have made more dedicated slots)