Unfortunately I think the "25%" is probably just an estimate for how much data left to incorporate into the game. So if they still haven't added almost any teams since they are waiting for the last transfers, then that data might constitute 25% of the game. I doubt there is 25% gameplay left to add etc.
As for the height and power suggestion, you are thinking in a good way.
I suppose you mean that you use the analog buttons on the PS3 and X360 to decide power and height. It is a good thing, but most PC pads doesn't have analog buttons like the more costly concole buttons, so in my humble opinion I don't think that is the way to go.
To be honest the "height and power" control issue is a big one. The best one so far is to simply tilt the analog stick in varying degrees for different heights (tilting it 50% is the "lowest" setting, tilting/leaning it all the way gives more height.
Or just pressing it towards your own goal makes the player try low shots.
With the tilt feature you need a pad with a good range on the analog stick though, so that you have good control over it. If thestick has too little movement the "tilt" sense it would get hard to control since you have so little room for the movements.
One thing that could be very useful though, is to use R1 to determine the height you want.
R1 is currently used for making Chip shots. But you could change it so that while you are powering up for a shot, you can also use R1 to quickly "power up" a height bar. That way, you can still use R1 to make chip shots (little shot power, and lots of height on the R1 height bar) but you can also try to make hard low shots (lots of shot power, little R1 shot bar). This system would not be mechanical, and often giving lots of power will make it very difficult to keep the shot down.
With this system, you could also for the first time try to slot it into the far top corner, if you give moderate power and moderate height. Would work great if L2+R2 combinations etc could be used to determine what foot to use and what side of the foot to use (instep or outside for example).
This heightbar would be great also for

longpasses. And it wouldn't be necessary for normal

passing, since you could simply use the

longpass with very low height to do low-longpasses that would look like slightly higher

passes.
Add a touch of Aftertouch curling (as transparent as you can get it) and you have total control.
Yeah, the L2 button freeing up is definately something KONAMI should do the minute they implement the analog stick (which hopefully is about one year from now. The way you could then combine R2+L2 for lots of tricks, or choosing inside-outside of boot, or just having 2 modifiers for passing, doing tricks with the right analog, etc is great.
You are right about the Throughpass button aswell. We could use the normal pass button to strike the ball into space.