what if instead of true damage, infinity edge did this?
critical strikes increase your damage to champions by 1% for 4 seconds (stacks up to 20%).
this would make marksmen damage ramp up over the course of a fight. they wouldnt just open a fight with a 250% stattic shiv crit like now, but their damage would ramp up when they stay longer in combat.
a 1% increase per crit might seem low, but there are marksmen that can attack multiple times per second. some of them up to 3 or 4 times with lethal tempo, or abilities like lucians passive. the new i.e. will make 100% crit at 3 items easily achievable. so it would stack up faster than it might seem. plus, a generic % damage increase would technically also affect abilities.
i still think a more conventional dps increase like this would be a lot more healthy than the true damage conversion.