Thanks for posting this. Like yourself and many others, I too have been trying to understand the new training systems and here are some thoughts.

Your first example (James Etheridge) suggests that training slows down a lot once certain skill(s) are above 140%. I believe this is more or less what some other forum members have been saying about their experiences. This is also in line with the old training system where a player's growth rate drops significantly once he reaches 140% (8*) overall quality. In your example, both Marking and Positioning are both just above 140% and you point out that training with Hold the Line has become much more difficult. The logical question to ask is, what if the skills being trained by a particular drill are a lot different from each other?

This takes us to your second example (Luciano Arnts). The 5 skills trained by Piggy in the Middle range from 25% to 275% with an average of 152%. He gained a total of 8% from 135% condition loss (9 greens), which translates to about 0.9% per green pack. Having looked up some of my old training data, this is very close to what an 8* FT under 21 used to get from training. I believe this gives credence to the theory that gains from training depend on the average (or perhaps a weighted average?) of all skills being trained under a particular drill.

If this is the case, then one thing you can do is train Arnts with Video Analysis, which covers his two lowest white skills (Positioning and Creativity) along with Bravery. In fact, this is what I have been doing these days. For a given player, I pick the drill that trains one or two of his lowest white skills along with maybe a couple grey skills.

Here is an example of mine after training everyone to death before the start of the new season:

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I just gave him 14 sets of Skill Drill, so 84 in total for 63% condition loss. He gained 11% in Heading and 6% each in Dribbling and Creativity for a total of 23% gain, which works out to be an increase of about 5.5 Skill% per green pack. This is more or less equaled to what a 3* or 4* young FT would gain under the old system, despite the fact that this guy is actually 7*. Granted, the lone white skill being trained here is only at 115%, but I do plan to power train the team once the new season begins. In particular, I hope to get some data regarding training gains vs. the average of skills being trained.

In any case, at this point I am fairly certain that a player's growth rate from training is now independent of the player's overall quality.