You want crit or a similar mechanic to act as an extra multiplier and make an AA based build workable, but you can fill in the same role with a "%damage increase on AA" stat (going to call it crit2 for the moment) instead of a rng function. The three main casualties of such a change would be yasou, shiv and IE, would need to rework their passives (ie could go to %extra crit2, yas would probably end up with a reworked %extra crit2 passive, shiv would probably end up similar to shen's passive, procing every x seconds and reduced by attacking, and would need rebalancing with PD), I know a few of the alternate map items also interact with crits but don't really have good ideas for them. Crit animations should be recycled into spell blade animations, sure that its possible to work them into a few other cases as well if you want to preserve them. No RNG, but the same multiplier effect.