I dont think you can call the controls heavily assisted,
its not like you can just tap the button and press in a rough direction and you will get a pin point pass. Also are you using the through pass button for through balls? If so why not try using manual passes, I have not touched the

button yet so I dont know what you mean when it comes to these automated through balls. If you dont like the cpu assistance on passes just hold L2, there is still some degree of assistance but that is to replicate your players stats.
Actually that is pretty much what you can do with the triangle through pass, though it takes more than a tap. Regular passing is certainly not "heavily" assisted, but the through ball button can be too easy at times. I've scored a few goals off through passes that I'd actually intended to go to a different player! I'll give the manual pass more a try but I'm not familiar enough with the control scheme to seamlessly use the manual pass modifier without having too think about it yet.
I really do not see the appeal of totally manual passing like in FIFA. When I first played FIFA10 I thought it was amazing but after I had got used to it and 90+% of passes were going where I wanted the novelty soon wore off, seeing every player on the pitch be able to play the most accurate passes regardless of difficulty was a bit crap IMO. PES has got the balance right with a manual modifier but still having the stats involved with the pass.
Well first of all, it's not "totally" manual - there is still an element of assisted, so in a sense it's a misnomer to call it manual. (In fact, a lot of folks are pissed at how much more assisted manual controls are this year. Lob passes in particular are quite assisted now.) Irregardless, player stats definitely DO have an influence on manual passing in FIFA, just as they do with the manual modifier in PES. Anyone who says they can pass as well with Pique as they can with Xavi with manual passing in FIFA is full of shit. Are stats as influential as they are with PES's manual modifier? Maybe not. But they do have an influence.
You must be one hell of a player if you average 90+% passing with full manual. I've been playing manual since 08 and on Legendary I average around 80-85% with top teams, which is a realistic accuracy range. With lesser teams I'll drop into the 70s sometimes, but still I typically stay in the 80s. Part of the problem though is FIFA specific - in FIFA, passing on semi or assisted controls is so unrealistic that it's near impossible to not finish games with accuracy lower than the 90s, so switching to manual is a means to add some realism into the game. To be honest, with the introduction of Pro Passing, passing in FIFA is all sorts of messed up at the moment.
But when you ask about what the appeal is, well that's simple: I want the ball to go where I want it to go; and when the ball does go somewhere, whether it be the top corner of the net or to the feet of my winger, I want it to be because I made it happen - or at least I want to "feel" like it had been up to me. The reason I switched from assisted, and semi afterwards, is because I got sick of seeing a pass go to a different player than intended. This is the feeling I still get with the through passing in PES. It can be beautiful to watch but somewhat unsatisfying knowing how much assistance I had from the CPU.
For people who never fell in love with manual controls in FIFA, I fully understand how this would be a non-issue, so I'm not saying this is as a criticism of the game, like say the more general complaints regarding player switching are. Rather I have come to have a certain preference and would love to see in the future a more manual option in PES. So I understood what Northzz was sayin.
Also if you are finding things a bit easy have you tried playing with the lesser teams? I have been playing alot of matches with Calcio Catania from Serie A and there is a nice degree of error with these players. I also have to take note of what player I have and pick my options accordingly. I have a guy playing right wing who has pretty bad passing stats, there is no point in trying to cross with him and unless I want to give the ball away short passes must be kept simple. He does however have stats slightly above 80 for technique and dribbling, this forces me to always try and run my way infield or into the box to make a pass. Having to play to your players strengths really takes the game to a whole new level both tactically and enjoyment wise over playing with teams where your players are all rounders.
Oh no, you mistook my opinion of the through pass for a general opinion - no, I'm sucking hardcore at this game at the moment. In no way am I finding it too easy. Quite the opposite really. I just understood what Northzz was saying about his experiences using through balls, that's all.