Card limit when stacking cards?

[MisChief]

Almost all the gold heroes I have that I use are at Dominion level.

All of them when stacked at 5 cards are only 80% success rate.

I've never heard or seen a Dominion level hero have more than 80% saint success rate.

Makes total sense, as the success rate is so low to start with at that level. Why limit the amt of cards tho? Just to add more risk I guess, but then what must you do?? Keep paying to insure and keep trying til it works? Sheesh - no end the the gem greed here is there??? LOL