Are you going to take this chance for sweeping change to do any standardization of Health/AR/MR Values across classes?
The difference between two champions in the same class can be absolutely massive:
e.g. Zac and Nunu are both AP primarily Jungle Tanks who's "tank" steroid ability is their healing, but Zac has 400 more base health than Nunu at level 18. (tldr please nerf zac)
Phreak made an interesting series of videos about Base Stats and the Physical Damage/Magic Damage durability skew of various champions a few years back and I rather like his idea of standardizing AR/MR base values and growths for different broad classes, for example:
Light Durability (adcs, enchanters artillery mages)
Medium Durability (melee fighters and battle mages)
Heavy Durability (tanks and juggernauts)
And then using base health vs health growth (the most visible and readable tank stat) as the balancing lever for whether someone is tanky early or tanky late....