If you take 0.29/0.2 and 1.10/0.75 you get pretty much the same 45% increase, so I dont see how its that much worse. Edit: I see my mistake, but leave it up in case someone thinks alike. So if you add the normal auto dmg then 1.29/1.2 isnt equal to 2.1/1.75.

Graves dmg at lvl 1 is calculated like this:

First pellet deals 70% ad, every other pellet deals 23.31% ad. Crit pellets deal 20% more dmg.

Melee non crit hits 4 pellets, melee crit hits 6 pellets.

If you have 100ad at lvl 1 the formula is:

(0.7x100) + 3x(0.2331x100) = 70 + 70 = 140dmg
If you crit the formula is:

1.2x(0.7x100) + 1.2x(5x(0.2331x100)) = 84 + 140 = 224 dmg
If you have infinity edge passive the formula is:

1.29333x(0.7x100) + 1.29333x(5x(0.2331x100)) = 90 + 150 = 240 dmg
It will do a little more dmg ingame because it rounds every number up.

For every other champ in the game except yone and yasuo the crit dmg ratio is like this:

non crit auto = 100% dmg

crit auto = 175% dmg

crit auto with IE passive = 210% dmg (or 120% of crit auto)

For graves auto in max range it would be

non crit auto = 100% dmg

crit auto = 181% dmg

crit auto with IE passive = 195% dmg (or 108% of crit auto)

For graves auto in melee range it would be

non crit auto = 100% dmg

crit auto = 160% dmg

crit auto with IE passive = 171% dmg (or 108% of crit auto)

Therefore infinity edge since rework is inefficient on graves because every other champ gets 20% extra dmg while graves only gets 8%)