The threshold for cause to award a yellow card would have to be upped massively, or it would be the death of the game.
The average number of cards per match in Scotland is roughly 4, so that would be 4 10-minute spells of uneven teams over 90 minutes every game.
The Sevco-Dons match in December had 11 cards (9 yellows, 2 reds) - that's 9 players off the pitch for 10 minutes at a time, not counting the reds (which admittedly were at the end).