Redefining Lost Champion Roles
There are several types of classes, but none of them are truly distinctive. This isn't because of intentions, but because of Item selections. Marksmen are building critical strike like assassins (meta Marksmen build); tanks are building ability power like mages (Malphite and Amumu, to name just two); Mages are building armor and magic resist like tanks (Karma and Fiddlesticks), etc. Assassins are supposed to unleash massive damage quickly, Marksmen are supposed to deal sustained physical damage, Tanks are supposed to protect their team by absorbing damage, Fighters are supposed to deal some sustained damage while absorbing enough damage to keep themselves alive, supports are supposed to provide their team with various boosts, and Mages are supposed to be the magic-damage counterparts of all the roles previously listed. Champions always reside in multiple roles, but this in no way diminishes the purpose of every champion having listed roles.
I propose a change to 3 core item concepts to encourage and better support champions in their various roles. 
1: Critical Strike. 
Critical Strike is supposed to provide access to burst damage. This being said, it currently deals double damage (or double and a quarter if one takes infinity edge) if a champion's basic attack critically strikes. The meta Assassin AND Marksmen build is to get 100% critical strike chance, enabling them to ALWAYS deal 200 or 225 percent of their basic attack damage. In essence, the Marksmen role has been transformed into the Ranged Assassin role.
I propose that Critical Strike be changed into Excitement.
Excitement: For the first 3 seconds of combat, the champion deals an increased ??% damage. Items containing Excitement will add to the champions ??% damage, but the duration remains limited to the first 3 seconds of combat.
This causes a differentiation between the roles of Assassin and Marksmen that does not currently exist with Critical Strike. Assassins will deal more damage than Marksmen in the first 3 seconds of combat, but then they fall off. Meanwhile, Marksmen will have the potential to deal more total damage than Assassins, albeit taking more than 3 seconds. Assassins will be happy in their role of deleting a specific target, and Marksmen will be happy in their role of being the Attack Damage Carrier.
2: Armor and Magic Resistance. 
Currently, Armor and Magic Resistance are fairly strong early-game, but becomes weak mid-game, and then remains weak for the rest of the game. Tanks, the ones that should have the highest Armor and Magic Resistance, remain easily destroyed, especially after they fail to defend their team and so are left totally alone, with little damage output, to face off with whomever of the enemy remains. As stated earlier, Tanks are supposed to PROTECT THEIR TEAM by absorbing damage.
I propose an added statistic to Armor and Magic Resistance that is currently found (in a manner) in a support item - Knight's Vow 
. I propose that all nearby allies of the champion holding Armor have a ??% premitigated physical damage redirected to the champion holding Armor. Likewise, all nearby allies of the champion holding Magic Resistance have a ??% premitigated magic damage redirected to the champion holding Magic Resistance. All damage will then be properly mitigated according to whomever the damage is going to.
Example: Ahri 
, with 50 MR, and Ziggs 
, with 50 MR, and Galio 
, with 200 MR, are all simultaneously hit by Veigar W 
, dealing 1000 premitigated damage to everyone hit. Galio will redirect 333 premitigated magic damage from Ahri and 333 premitigated magic damage from Ziggs to himself. Ahri will redirect 167 premitigated magic damage from Galio and 167 premitigated magic damage from Ziggs to herself. Ziggs will redirect 167 premitigated magic damage from Galio and 167 premitigated magic damage from Ahri to himself. Galio will now receive 1332 premitigated magic damage; Ahri will now receive 834 premitigated magic damage; and Ziggs will now receive 834 premitigated magic damage. Galio will lose 444 health, Ahri will lose 556 health, and Ziggs will lose 556 health.
Ultimately, Galio received an extra 111 damage to protect Ahri and Ziggs from 111 damage each (222 total damage).
This will encourage Tanks to build resistances to help their team instead of just getting damage.
3: Lifesteal. 
Lifesteal is intended to help a champion sustain his/her health by healing according to the damage the champion deals, however, directly converting damage into health causes lifesteal to primarily help Assassins, secondarily Marksmen, and thirdly Fighters. Lifesteal is supposed to primarily and equally help Fighters and Marksmen, and thirdly Assassins.
I propose that Lifesteal's direct damage-to-health be changed to indirect damage-to-health. Each percent of lifesteal of each percent of the enemy's maximum health destroyed should equal the percentage of that champion's maximum health.
Example: Caitlyn 
, with 1500 max health and 20% lifesteal , deals 400 postmitigated damage to Olaf
, with 3000 max health and 20% lifesteal , while Olaf deals 200 postmitigated damage to Caitlyn. (Caitlyn does more damage because of damage items while Olaf has more health because of health items). Caitlyn hurt Olaf by 13% of his maximum health, and Olaf hurt Caitlyn by 13% of her maximum health. Caitlyn heals (20% of 13)% of her 1500 max health, and Olaf heals (20% of 13)% of his 3000 max health. Caitlyn heals 97.5 damage and comes out with a total health loss of 102.5 (0.068% of her max health), while Olaf heals 195 damage and comes out with a total health loss of 205 (0.068% of his max health).
This shifts lifesteal to primarily and equally help Fighters, Marksmen, and thirdly Assassins.
If you like these three balance ideas, please like this post to help others see it too! If you have anything to comment on, please comment below. I want to hear your comments! Thank you for reading.