As for DMI, it is not pointless at all. It helps you track training, form changes that are less than a visible level, and injuries.
I disagree. Nothing is better at tracking training than little green arrows. If DMI can drop while skills increase, it can't possibly help you track training. Unless you know something I don't about injuries and DMI, I find it best to look at the injury notification on the player page to see whether or not a player is injured. I agree, however, that it may help track form changes within a level, particularly on players who don't receive training.
At the risk of going further off-topic, if DMI weren't pointless, why does it stand for "Deliberately Meaningless Index"?