This is simple, manage your team like Arsene Wenger, then you will have a bit harder ML.
I don't agree. Lately I found a hole where I can build a full Allstar team without obliterating every team in the league (especially the spanish league).
Simple, build a team of Stars whom their age is over 30-33. Players such as Lampard, Drogba, Milito, Beckham, Cannavaro, Viera and the list is just going on. I promise you, unlike building a team full of 16-19 years old ~70 rated kids, where you only need to pus the sprint button and they will pass any defender and score easly, you will have some difficult times. Playing with a team with Drogba on the FRONT, Lampard in the middle, and Beckham at the side, might seem overpowered, however, these guys are old and are lazy bastards, and the more time passes, the less they become good, or evne decrease, where things will only get harder.
I made a team full of the old galacticos team of Real Madrid (Ronaldo, Raul, Beckham, Zidane etc) and they are all at least 28, most over 30, with ratings of AT LEAST 85. I'm currently with 39 points against 53 of Barca and Sevillia, and It's march. I'm a great PES player, and I have taken Triple four times in a row with Liverpool while still playing with Riera, Benayoun, Kuyt, Babel, while Gerrard and Torres are my only 85+ rating players in my team. I sold Mascherano, Aquilani and Agger since they were just too good. Didn't help it, and things were still too easy.
This is all from my own experience and ways to find out how to make PES harder, without playing those shitty unknown default players, but with real class players who you admire.