If every kit had Lee Sin's design philosophy...
Let's play a game. Let's add something to a champion that really feels tacked onto. As in, it feels like it's there just because, and adds a weirdly, small-enough-to-be-forgettable, strong-enough-to-matter amount of power.
Lee Sin'ize a kit.
I'm usually not one to complain, and I don't dislike Lee Sin, but a lot of what he has in his kit feels completely redundant.
Example:
Pantheon now can W himself, (obviously) not stunning but refreshing his passive (In the same way Lee can Safeguard himself).
Passive - On ability use, Diana gains 50% attack speed for the next three basic attacks. On the third, she deals damage in an area and restores mana.
Q - Targets hit are marked with Moonlight, revealing them and reducing the damage they deal by 10%.
W - While the shield is active, Diana gets 5/10/15/20/25% spell vamp.
E - Targets hit are marked with Moonlight, revealing them and reducing the damage they deal by 10%.
R - Hitting a target marked with Moonlight removes the debuff from that champion and deals 8% of missing HP as magic damage.
's W gives him a movement speed boost.
"I think we need to have a talk about your obsession with magic..."
After casting Parrrley, GP gains bonus attack speed, and his next two basic attacks regenerate half the mana that Parrrley costs. (If GP kills a minion with Parrrley and AAs twice, he regains all of his mana back)
and 
i think)
If Fiddles attacks a feared champ, the fear spreads to all nearby units. If Fiddles drains a silenced or feared target, he deals double the damage and gains a shield of the excess health grown. His ult also now does 100 more base damage and roots all enemies.
Q now also slows attack speed and gives Ashe bonus attack speed
If W hits an enemy champion, Ashe can recast the ability to shoot another Volley
E now reveals and slows enemy champions hit
R now travels 250% quicker when within 2000 range of an enemy champion
Q now resets upon killing an enemy unit
W now also gives bonus attack speed
If you hit E, you can reactivate this spell to gain 20 Fury and gain 10% movement speed when moving towards enemy champions hit
R is now a toggle with a 13/11.5/10 second cool down, still launches
Hitting an enemy unit with the original Q projectile stuns the enemy hit and causes the 2 made projectiles to orbit the unit if the unit hit was a champion
Killing an enemy unit grants a charge for your W, champion kills grant 2 charges and causes your next W to have double range and damage
Your E's AoE radius is doubled if you have recently taken damage, tripled if the damage was from an enemy champion
Your R is now a global and has it's current duration reset and tripled if you score a kill or assist during the ultimate
' Q crits.
Whenever 
's health goes below 0 he procs his passive. (Procced when GA is not on cooldown, procced under the effect of Zileans ultimate)
When 
kills something during his ultimate the duration is increased by 1 second.
When 
presses Q he frees himself of slows.
If an enemy dies to 
's spear, the spear keeps on moving.
When 
poisons someone he can detonate it to heal mana based on how low on health they are.
That's it.
Casting Black Shield on a target also grants Morgana 20% Lifesteal for the duration.
When Urgot activates his Terror Capacitor, a small portion of incoming damage would hit his Mana instead of his health. If an attacking enemy has been hit by a Noxian Corrosive Charge, damage from the target would regenerate Urgot's Mana.
Upon using Event Horizon Veigar gains temporary AP per enemy stunned.
No longer use resources.
's dance now causes him to juggles his axes, gaining Draven stacks for each time he catches them while doing so.
Can now lunge towards friendly units and wards. Lunging to a trinket ward refreshes the trinket's cooldown.
Can now tag himself with his Q, increasing his movespeed and attack damage regardless of where he is.
His E now pushes and damages enemy wards. Vision wards do double damage when flung.
Can now teleport to and shield himself.
Can now attach time bombs to wards. The ward remains invisible.
Can now target himself with his Q, dealing no damage but gaining the shield and empowered auto attack.
Can now attack himself while using his parry to increase its damage.
Q to himself or wards as a starting point.
Can Q himself to deal no damage but gain 3 stacks.
R now also targets all enemy minions and wards and all jungle camps, including Dragon and Baron.
Can now Q himself, dealing no damage, but healing for twice the normal amount.
lands his Q on a target that is alone it marks them, he can recast his Q to deal the damage again and regain health equal to a portion of the damage done.
can leap to any champion hit by his ult.
now uses energy....
