I won the cup with one account the past season and found it easier after trying to tank 2 seasons in a row and being unsucessful at it for some reason. Seriously. I was down to 2 and 3 * players after coming in 7th and 8th and being promoted. I tried to tank both seasons and had issues with winning even with moronic formations and playing with my worst players.

It seems that the lower quality of your team ensures greater success. If you win leagues, you get harder opposition. I prefer that theory over the others.