Under the help section there should be a selection that leads to a small guidebook. This would be a text (and maybe pictures if you feel really fancy) with page scroll. (either use the bumpers like in after battle screen to move between pages, or have it be one long scroll)

This guide should contain the following:

Damage Profiles
Scanning Explanation
Channels (Joining, Making, Leaving)
Befits of squading
Equipment descriptions (all side by side)
Dropship controls. (Probably better as a video in game, or set of pictures)
Vehicles Comparisons (Weapons vs Weapons, Armor Types etc)
Skill explanation (One the player can always reference)
Income Guide (How to stay ISK positive)

You'll note most of these things have parallels that can be found out of game, but for many new players, they are not used to, or unwilling to doing research out of the game for a game. As such, general guides should be made available in game for them to find, and learn from without the need to leave game to find.

The information here should be basic, and bare bones for example with damage resists just give the % done against armor and vs shields, and maybe have a few example weapons next to them.

Scanning should explain the three ring mechanic, and how to spot / avoid spotting somebody.

Effectively, this guide should contain all the basic concepts you feel DUST players should know, so that they always have an in-game opportunity to find it. A text file would not be overly demanding to add, and would add some in-game documentation to many facets of the game that has changed over the past year. This is not a full measure that would fix many of the learning curve problems, but as a text file addition it would be programmatically light to add the elements to insert it into the game, and can be largely done by a non-programmer (Such as the illustrious Rattati).