Always hated how the Eldar are described as giving up armour for speed and yet it not having any effect in the game since 2nd edition - and only then because they could run over 10" and thus get a -1 to being shot.

Their initiative was higher than almost anything so they would always win draws in melee, representing speed. Their vehicles had very high combat speeds allowing them to get modifiers while still attacking.

8th ed has no speed modifiers and no initiative.

So I thought a racial rule that applies to all aeldari would make it simpler and easier to work with.

Sublime grace
Eldar are preternaturally fast and graceful. Their speed is almost impossible to behold, their quicksilver forms never staying still long enough to see them.

All aeldari units possess the sublime grace ability. When making hit rolls against a unit with this ability, 1s and 2s automatically fail irrespective of modifiers.

Things like Holofields can then add to this and other special dodge rules.

Is basically a -1 to hit, without the calculation.

Alaitoc would convert to +1 armour in cover