all these percentages just convolute balance more and more and add more variables that make the game less accessible. @OmarTheDank , said it really well, keep it super simple - KISS.
Literally as OP you edited your post to show, make it about mobility and armor.
This does still leave in question what effect this has on healing hence all the % issues as we don’t want to go back to un-killable heavy armor healing builds. This is the issue in why damage is affected by armor because people were literally immortal paladins in heavy armor with S&S, and sustained healing was un beatable.
That overall imo is an issue with mana management and the potion CD which could be increased. If within a minute or minute and 30 second window the healer goes (OOM) - out of mana - then they can’t heal.
It takes the principles of raiding from games such as WoW. If you cannot kill this boss with DPS in under 2 minutes he enrages and wipes your whole raid.
Similar principle, if your team can’t kill the DPS in 1 minute and 30 seconds you lose mana and wipe.
This would create higher skill cap for healers - make mana regeneration something that requires thought , and probably total mana pool would need to be increased.
You would have more chances to heal/cast spells but when your mana ran out it would be more punishing.
A longer potion cooldown would also prevent these pesky light armor users from getting away in just the nick of time to use a potion.
As another point, many of the stat lines have very useless perks. For example for intelligence and most mages, the 300 stat perk is pretty useless except for musket builds.
That is not what most mages want to be and is very niche. Yet for strength the 300 perk feels like a massive milestone and game changing perk, as it does for dex with an ondemand critical hit.
the 250 con perk is pretty useless for the most part and desperately needs a re work.